I am kind of surprised to see all of the comments regarding why they would use the virtual currency. It makes sense. They can offer you more by keeping you locked into their ecosystem. A crude comparison would be a company like Gamestop giving you more for your trade-in if you take in store credit as opposed to cash. In store credit guarantees that you stick around.
At a business perspective, it makes sense but I think they are curious to know why the virtual currency is valuable to them.
I'm glad you brought the Gamestop example up. Gamestop gives you the option of selling for store credit or cash. If you take cash, they give you 50%. We can offer more than market value because the overhead for us is minimal since we're dealing with virtual currency. The value of the currency never changes and we're always trying to sell for the lowest amount possible to provide value to the consumer.
So certainly valid questions on here and would love to answer as many questions you have!