Some people didn't want to miss the train while some people know what they're doing, as simple as that.
For me, there are no coins that better than Bitcoin, that's why I keep invest in Bitcoin and hold it.
If they really want to invest then they should have bought Bitcoin when it didn't reach the price of bitcoin today.
Investing is for long term purpose, if you're looking to make profit when Bitcoin reach to this level, that's not an investment because you're looking for short term profit.