I don't really understand the problem of mining from free sites, but in 2017 I've done it several times, the results are in the good category and not a scam, after that I never do it again, because my focus has been on the bounty, indeed there are some friends who say that mining on some sites is usually a scam, but because at that time I wanted to try it I continued to do it, and today I have not heard of the mining anymore
Mining from a website are called cloud mining and they actually work when the time cryptos are not yet popular because the difficulty of mining a coin that time is not hard as today but today almost all cloud mining sites now are fake. You switch on the bounties for that same reason right? but even in bounties the scams are also rampant and of course we should not forget that airdrops suffered the same fate.
It's so sad that the great times for earning a free cryptos have come to an end. If you want to earn a crypto right now, you can either buy it, stake it, or mine it the traditional way or by using a miner but that's not going to be easy now.
I have seen almost no more mining sites for now, even if there are only untrusted sites, the changing times no longer provide a place for free to do mining, now the pattern has changed by way of purchases, so it's no wonder for now sites -the site is no longer visible, so the previous perspective can no longer be run for now, because of that the shift in mining methods has also been included in the category of using technology