You can add an option to convert balance between the supported coins, which may be an interesting way to earn a little more and also make easier for users to withdrawal
We actually can't do that. That would be more of a currency exchange and has totally different legal footprint that just being a casino that accepts multiple currencies but pays out in the same currency as deposited. So we will most likely never do that.
Yeah, very much understandable, could as well open the casino to more risk of hack as the longer a code, the higher the chances of an error that could lead to a big problem.
And to be honest, this is one of the features I used to wish that casinos had, I mean, It would be super convenient to be able to convert from one crypto currency to another withing the casino, but later on, I got to understand that it carries some serious legal implications as authorities may deem this feature as a currency exchange that needs it's own licensing, and this is why even big casino like stake didn't have such a feature.
And with the way cryptocurrency exchanges has become major target for hackers, it's dangerous to have that running a casino - just my thought anyway.