Actually buying when the market is in dip is a very difficult step to make as not all dips will guarantee earning because what most commonly happening now is when you buy the dip but it dips even more losing your investments so maybe buying the dip is applicable for Bitcoin only but not with the Altcoins.
You are right that not all dip is worth it. For bitcoin, it will come back if we have a little patience as it has happened after 2017 and it bounced back. The same might not be said with altcoins, some altcoins dip is the end for that coin. I have experienced this with some altcoins.
I disagree, all dip are worth it because bitcoin is expected to rise again, buying at dip will give you a good value and that you can sell at a great profit.
This year, if we were able to do the right timing, we will be able to buy the best dip at $3K +, and we can sell at $13K, well, that's only possible if we are really smart enough and lucky at the same time.
What I learned is that we should always buy every time the market dip, especially if the market is healthy again.
In my evaluation, the market movement for BTC is healthy this year, so buying at dip is advisable.