How about starting with the most elementary basics of getting into crypto? How do you vett a likely winner, how do you know if you can trust the flagged wallet, what kind of equipment should you have at your disposal before even thinking about downloading anything? What kind of time and effort will be needed once the wallet is installed? What kind of power usage and heat generation can you expect? You know, the most ELI5 stuff you would want to know before downloading anything.
Eta: and thanks. Don't mean to get all cynical but I've been interested for a long time but without trusted Intel on the matter
In my case, I joined a forum several years ago called Bitcointalk to learn about Cryptocurrency and mining. There was and is a section there with new Alt coin announcements. I used to mine every coin at launch. That's when difficulty in mining is extremely low and block rewards are extremely high. It's never too late to begin.
As far as picking a winner, the only thing I can suggest is to study the fundamentals of each coin. How is this coin better than others? What are the block times are they 60 seconds or 10 minutes? What is the total supply to be mined? Is the coin minable? Proof of Work or is it Proof of Stake? Was there a premine by the founders of the coin? If so, how many coins did they get?
It's a long list of considerations to compare and contrast. And in the end, the coin you thought was a winner may end up as nothing while another coin that started as a joke (Dogecoin) races to $1.00 (I mined that at startup too) My philosophy was to mine everything new at startup in case there is a winner in the bunch. (It worked.)
How can you trust a flagged wallet? All wallets will be flagged. You can run a virus scan on the wallet to check for normal things and hidden things. Run thru the results and determine a case by case basis for each result. One of the most common results flagged will be the miner portion, if the wallet stakes or mines coins it will show up as malware usually "minerd". If this was an email you received, I wouldn't open it, but since it's a Crypto wallet with a mining function built in, of course it's gonna be there, it's supposed to be. You have to keep in mind the goal of the Cryptocurrency. The founders of a particular coin stand to make a lot of money if the coin works out and catches on. They couldn't hope to earn much by attempting to hack people to view their browser history.
I use old equipment on a day to day basis. Not because I'm afraid something may happen because I have a wallet installed, it's simply because I'm frugal. I would suggest if you are concerned something may happen you should use something you're not too concerned with. And that would apply for any program or app you may install not limited to Crypto.
As far as power usage from just running a wallet, it's extremely low. No more than any other app and likely much less than an internet browser. However if you enable mining your cpu will run 100%, because mining is a cpu intense operation. If you're just using the wallet to send or receive coins, power usage is minimal. There's no need to enable mining if you don't want to mine new coins.
Added info: I just checked and the entire network for ROI coin is running at 584 H/s (hashes per second) to better give you an idea of how little power it takes to run the entire network, 106 H/s of that amount is being done by my antique i-7 desktop......Now that's efficient.