But this is a serious distortion of the standard of care.
Why would prescribers want to make guinea pigs of their patients? What's in it for the provider? Write up the results and get it published?

You have an active imagination.
Because it really might help the patient, as much as anything.
True story: I was able to get to a neurologist once, who gave me my official dx of epilepsy. (I'd been hospitalized twice already, recently postpartum, after gran mal seizures. I also had a couple of gran mal seizures when going through puberty, but they were classified/misdiagnosed as convulsive syncope at the time. My grandfather was epileptic, and my uncle was epileptic. I knew I was having seizures, but I didn't know that literally WAS what epilepsy was, even if the seizures were that infrequent. I guess I was assuming it was only epilepsy if you had seizures at least once a week for years or something.
Anyway, after getting out of the hospital the second time,
needing to know
wtf was wrong with my brain was the thing that compelled me to finally get the internet for the first time, and I'd been google searching terms that would help explain
why I had seizures at apparent times of great hormonal upheaval (puberty and postpartum,) and I was only getting from google original research articles which were taking me something like 20 hours to
even read, because I had to look up the meanings of not just the words in the articles, but the meanings of words in the definitions, too, sometimes 4 or 5 layers deep, just to get through a single sentence actually comprehending what I was reading.
So, I'm in the neuro's office asking him if maybe I can get referred to an endocrinologist to see if my hormone levels are totally wacked out, talking about the role of neurosteroids in epileptogenesis, and maybe see if treating THAT, the possible hormone goofiness, prevents my seizures if so...and he becomes all giggly and delighted saying "Yes! Yes!!! Oh, you are the perfect subject to try this with and it really might work! We'll write up a case report together and it will be so exciting and will be a SIGNIFICANT contribution to neurological science! Oh, but I have to warn you, this is totally experimental and not the standard treatment. You are absolutely my guinea pig if we try this. We will be the first to ever try this."
Which...gave me pause, first because I really had assumed something like what I was thinking was probably the first line treatment for someone like me, and two, holy crap! Doctors and patients can just, like, conspire to MAKE SCIENCE LIKE THAT? How totally awesome, yet vaguely terrifying is that? I had learned as rote memory the process of "the scientific method" in school, but it had never actually really clicked...not like it did right then, where I'd inadvertently designed the experiment and volunteered myself up as the subject, too, all as the result of my existential terror over my mysteriously and dramatically malfunctioning brain.
I chickened out and decided to just take Lamactil, his current favorite standard of care treatment (because if kindling theory was right, I was probably one seizure within the same year away from have many, many, many more seizures much more frequently.)
As he was leaving the room, I asked "So, what's wrong with me?" and he was like "What do you mean?" and I was like "I mean, what's my
diagnosis?" and he stares at me with this blank stare, and then burst out laughing, and says "You know about kindling theory and the role of progesterone in possibly preventing would-be seizures, but you didn't know the name of what's wrong with you? You're just epileptic. What you have is called epilepsy" and then went into how idiopathic means "we don't know" and how my family history means there's probably a genetic factor at play in addition to who knows what else. And I was floored for a week that I'd been an epileptic for at least 15 years without even knowing it, and that I'd just read all that neuroscience without ever even encountering the notion that an epileptic is just someone who has 2 or more seizures more than 24 hours apart, not caused by an immediate head trauma, or a tumor, or fever from poisoning or hyperthermia, or some other possibly deadly thing like that.
I can't help wondering just how small of a patient population this could possibly apply to. People who take an abortion pill then in the next, what, 12 hours, change their minds?
It also sounds like something which it will take ages to collect enough data to know for sure the fetus won't be adversely affected.
Perhaps I'm not understanding what this pill is for.
Pro-lifers are obviously banking on the pill's very existence and legitimization somehow magically increasing the number of women with after-last-minute regrets.
I do know factors like feeling bullied by parents or partners into getting a regular/D&C abortion, combined with the pain and invasive nature of that sort of procedure itself, does cause some small subset of women to regret having gotten an abortion.
No idea what the small number of women who regret doing the pill version are, though. It probably depends (like the D&C) on if they felt forced into it by other people, and if they're given pain meds.
I know I've never encountered
even a single "I regret my abortion" "testimonial" (used as "propaganda" by pro-lifers, but many are obviously heartfelt) about regretting taking the pills. Maybe there's actual, real data out there on that question somewhere.