There is a fine line between being a gambler and risking stuff and being an idiot. If you keep all your money on fiat or btc, you will do not bad, but you will not do INSANELY good neither, there will not be any 10x going on at all on your portfolio.
If you buy the 754th biggest coin which will definitely be a shit coin, you will have a chance to make 10x but at the same time have the same chance to go bankrupt as well, which is a very risky in between zone.
But, if you make a portfolio of the top 20, that means they are both good, but also have a chance to go up as well, that is why its both a decent level of risk but decent level of potential reward as well, I agree that buying the top 20 with exception of some bad ones in there would be the best idea.
Just an update on my portfolio, I sold my bitcoin holdings a few days ago and went 100% all in on Alts specifically Eth,BNB,ADA,NEO,EOS,TRX and BTT.
So far in the last few days my portfolio is up by a far greater percentage than if I'd just held BTC, so fingers crossed Alt season is finally upon us
I personally think I'm far more likely to make a decent profit from Alts at least in the short term, I'm not averse to selling them at a profit for BTC though.