At current they are dealing only in top and most trusted coins like bitcoin and ETH as crypto deposit but I agree with you that fees are quite high.Eth is relatively witnessing much higher gas and network congestion which can be a issue but if we you withdraw one big amount instead of cashing out your small winnings you will pay less fees automatically.They are also planning to add LTC which could possibly cater to fees problem and promote the casino to more users with advanced gaming and crypto trading experience.Just waiting for more development by the casino which they are showing in good manner.
Maybe with the question of when to add other options it will be resolved soon because the developer has planned in the future with this LTC coin, you can say good news and small capital gamblers don't have to worry anymore, you can bet freely.
With trading sites, I don't know yet, meaning the developer hasn't provided details here, which is clear that this feature will be useful later after the team finishes it.
Rollbit should be able to provide exchange to other coins so that it is easier for gamblers to change what they want in this case as it will be more interesting in my opinion.