In my own opinion if bitcoin has its high price therefore I will going to sell my bitcoin because we can't predict what happens next so you better be wise. Of course if we are going to buy coins just make sure that the price is low so that when you are selling it you can have a lot of profit.
well if that's your decision, as you say we do not know the future. did you ever think that the scenario you are selling btc on this day with the price of 4500 $ then two weeks after you sell the btc price rose to 5000 $, think of the scenario !.
The popularity of bitcoin from day to day will be more popular because people will like efficient bitcoin instead of having to deal with the troublesome fiat.