PlayStore is terrible to download this kind of app. The reviews are completely nonsense and irresponsible: you find a mining or faucet app, then you look the reviews and there are lots of 4-5 stars and when you look what they wrote you see things like: "testing, looks good", "wasn't paid yet, but I will give 5 stars for now"...
There is no way to really know if that app is legit or not. And in some cases they start legit and in the end scam the users and worse, steal their informations, with serious chances of invading cellphone's data. I reached to the conclusion it's better to not download any app on cellphones if you really care and want to preserve it for a long time.
Could this reduce the confidence in Bitcoin and other legit crypto-currencies?
Only people who aren't really interested in BTC and Crypto in general will let a negative app experience affect their confidence about it... Just don't download these stuff and you will be fine, use a browser, use popular legit sites and there won't be issues.