I haven't used it that much, but from what I've heard from my team mates at office who have bought more, I think you can add money to your wallet on their site and when you think it is a good time to buy, convert them to whatever cryptocurrency you want.
But by default and the easiest way that I have tried is to convert directly to the crypto I wanted (Ethereum) when the transfer got completed. Their support was great, at least at the hour I was talking to them, they got a pretty short reply time in the chat and are very much willing to help their customers. It is true that this is a startup, but by now, my overall experience was great.
Indeed this is a sign that cryptocurrencies are getting more popular each day, that's why we have seen a lot of companies growing on this new field of activity in not so popular countries, and this makes me think that it is just a matter of time until they will become mainstream.