its depends on your style.. if youre an investor your strategy really is HODL for long term but if youre a trader ofcourse youll trade when you already have profit and just buy again at dip
using this strategy you need time, and you have to maintain your coins, and this strategy needs time, if you want a fast money, why don't you join the trading?
You can do both if your really want to, holding major coins for long term purpose while doing day trading are the best way to easily earn profit here in crypto world. I think you already have an idea what coins are best for long term holding and how day trading goes. I know you need time to fully adopt the system and also experience will give you much better chances of succeeding as a trader.
I think hodl strategy is still effective but it will all depend on the holders decision since there are factors of why a person hold such a particular time of its coin and that is all for profit but a financial needs is a turning point of every holder whether to sell its coin even if as not as big as he/she wait.