but if you have a mentor who only teaches you because you pay for his teaching, I think it is better to just self-study, because what you will pay him is better to have him buy some of the top altcoins and then hold them while studying crypto trading, what do you think? isn't good or bad idea?
That's BS.
These mentors that would like to teach than to make money for themselves, they're only in it because they can easily make money from those newbies.
I agree to just self study but maybe some of their personal experience and teachings could be of useful for someone who aspires to become a full time trader.