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.