Crypto is wild west. Scams/hacks, all the new ways to get compromised never ceases to amaze me. Yet, it remains one of fastest way to build one's portfolio, once you have made enough, secure it, diversify in real estate, gold, etc.
You could having million dollars worth crypto in your wallet and next moment, puff it's gone.
In light of all the recent exploits and vulnerabilities in crypto, it's a good advice. Diversification is a key topic for discussion and while a lot of bitcoin enthusiasts would frown at the idea, I really think it's a good one as the hacks that have happened in recent times were on chain and some times, offchain (eg: An attacker taking over the DNS of a website domain and routing users toa phished version). In some pf those cases, the user didn't need to do anything to get compromised (see mixin hack).
The key is to stay in crypto. Many people join the bandwagon, get something good going and then lose it all.