This will be a good time to sell-- bitcoin is going down and people are just dumping on it. Meanwhile on the other side, people are getting the scraps of bitcoin that they can lay their hands on hoping that there will be a next bull run and make themselves rich. but if you are going to study the trend for this year, it is not looking good for the upcoming years for BTC. New coins are emerging and soon BCH will overtake BTC.
I strongly disagree, notwithstanding the dumping price, I think it isnt a good time to sell. Rather get yourself ready to buy bitcoin. Prices may shoot up very soon so take the pledge now.
This bitcoin price decline will be short time event, now it's time for buying not for selling, who sell will make a mistake, big one, never sell in dips and buy on tops, those two mistakes are the most common in crypto. People cry later for their bad trades, instead to make money they will lose.
Why people should buy bitcoin? They can invest in long term holding, they can try to trade with bitcoin and try to make some profit like that, to invest in some services or simply to have fun. Whatever reason you choose, combining is an option too, it's good to be here and involved in crypto.