Well, I invested in Bitcoin when the price was $4600, then it started to drop the day after. It didn't stop until it hit $2900. If I was a short-term trader, that would've been an unfortunate time to invest. Look at the price now though, a month later.
Everything you're talking about has happened in a very short period of time, so I don't really get your point here. Long term in my book is when you hold your coins for at least a year or two. If we look at the time frame you bought, when the price went down, and when it recovered to where we stand right now, it's extremely short term.
I just showed that short term fluctuations like that don't matter if you're holding long term (for at least a couple of years, like you said). Even if the price recovered in a short period of time, it demonstrates how it always reaches new hights, even after significant dips.