The dividend capture strategy is based on an investment technique that focuses on quickly capturing the dividend issued by a corporation, without intending to hold the investment over a long period of time.
ex: bitcoincash, bitcoingold, etc. or any other coin fork/split...what to do & when to do it

Of course you can always sell those free coins if you want to and re-invest it to altcoins and bitcoins itself. But there are those who loves to hold specially bitcoin cash because they think its a good coin to earn good profit. It was evident last November when it is all-time-high and reaches more than $2K.
It's easy to sell them at trading platform that supported it. When? Most do it once they received the free coins. No qualms about it. Just dump it once you got it. Its free money anyways.