Investing in top altcoins has lesser risks than most new altcoins, look what's happening presently, many new projects are now turning into DeFi just to take advantage of the HYPE, if I am holding any crypto project that isn't DeFi from scratch I will dump for another altcoin
I noticed that altcoins in DEFI category are doibg great presently and like you mentioned, most altcoin projects are adding DEFI to their project aim. It's funny how a sport betting project switched to DEFI, just to take advantage of the hype. This is the more reason why most altcoins are good for flipping as mentioned by OP. Just ensure you hold altcoins in the current trend. I remember when it was exchange tokens, then deflationary etc.