Exchange coins are becoming more profitable nowadays unlike back in the days. Nowadays the tokens good exchanges which are changing this space are rewarding its users, although it has its own ups and downs. But the main point is, holding the token of trustworthy exchanges is far better than hold some random altcoin which has no future. Take a look at Binance exchange and it's token, who wouldn't want to hold it bearing in mind the exchange keeps advancing for good. So in my own opinion I would say, the reason for price increase is owing to how solid they are.