as for market cap, that is the problem nowadays with people, they think just because a website called coinmarketcap.com ranks a coin on top then it must be good or safe to use!
Most investors and traders response, when newbies asking which coin to invest with, I am sure more of them will response just choose top 10, 20 or even 50 in the market to be safe (pretty sure they are referring to CMC). There is no such thing as safe, cause even bitcoin its still risky. Dont see much difference aside from the centralization of tether and btc when it comes to OP's topic IMO.