I think that's right, but for another reason : if you're new in bitcoin, then it's statistically more likely that a crash is about to happen (because of how the hype machine and bubbles work). So in that case, spreading the purchases over some time is probably better indeed. Or you could wait to buy after the crash, but in bitcoin's case it might be risky, because if you noticed the bubble early enough, the low after it pops might be higher than when you were ready to buy at the first time.
Exactly. Good luck picking the highs and lows, but if you are thinking about buying bitcoin for the first time others probably are too. Instead of throwing it all in and praying you didn't have horrible timing, DCA allows you to get a good average price no matter what happens in the short term.