Well buying is a bad idea - people should have done that before all the hype about the ETF coming soon which has dramatically pushed up the price.  You should only but if you're very optimistic about the ETF or you're prepared to hold for a long time.

Selling could have been a good idea recently - it was clear for a while that it was staying near $1300 before it then fell down to around $1200.  If you were clever enough to notice that temporary climax you could have sold then and bought again about now.

In my view, there's an option missing here, which is trading.  If you're clever enough then during this time of volatility you could earn some decent money by buying and selling repeatedly in ways which earn profit.

For the less experienced in the market like me, the best option is to hold because I know that eventually Bitcoin is going to rise much higher.  It could well take a year before the network issues are sorted out and it becomes good enough, but that's okay because there's no point making a rash decision to sell during this (probably temporary) high.