Looks like this is going to be the trend for more and more dicing sites and crypto casinos. I suppose I don't really mind if I can't exchange currencies, I mean I deposit the coin I want to gamble with and don't really gamble with alts. But I understand that sometimes it could actually be easier to just deposit what you have (usually Bitcoin) and if you feel the need to gamble an alt, instant exchange is a great alternative.
Probably also it saves time and money!
It's really a trend now that casino's has to make their integrate exchange, it's up to them if they will tied up with an establish exchange or they can create their own brand for their users.
There are gamblers that does want to gamble with bitcoin and sometimes change their minds and want to cash out with other alts, vice versa.