When the price is so high of course holding is good

But why the price is soo high, can someone explain me? Please. I want to buy btc but when the price is under than $1600/btc, how someone can invest in it?

Huge adoption over bitcoin is the reason to see the continuous increase in the bitcoin price chart. Segwit and BU also passive pull ups for bitcoin to grow everyday. Simply do not think that bitcoin bump only reason to take hold the bitcoin.
This bitcoin holding is global truth to grow your bitcoin value which is in your wallet. So do it always and buy it from localbitcoins.