Recently I asked if there were any updates (because I knew from the first transaction that they were a slow-ish artist) and they admitted that they'd forgotten completely about it and asked if they could simplify the piece a bit. They said they'd drifted away from the site.
As my husband's birthday was coming up, I asked if they could change it to a couples piece of our characters and they were happy to do so and then I didn't hear anything from them for a while.
When I asked for another update, they sent me the finished piece and admitted that they felt like they weren't really being paid as they weren't using the site anymore. I asked for their paypal and sent them a tip (because the work was frankly amazing) but at the same time I feel a bit put off. I don't have a whole lot of "play money" right now which was the point of me asking people if they were taking the game's currency for commissions.
So, my question for both commissioners and artists, how would you have handled the situation? Do you feel like you're not really getting paid if you take a game currency commission?
Edit: Thanks, everyone, for all of your responses. Responding to everyone with the same thing is a bit silly so I'm putting it here. I feel really reassured about this whole transaction and I'm glad I'm not the only one who felt put off by the comment.