Because it's a network for gamers so why not making it decentralized? Also it's really useful for the "services" part of the app. And we will see everything builded on blockchain in the future
Even Steem is working real hard to get a solution for the internet speed problem. I know that its a general issue but it will affect the usage of all the online brands.
Internet speeds are a real problem, especially in the US. There are still people on dial-up ffs.
Internet is fast everywhere in the world now. Only in remote places, like some pacific islands, you pay a lot for very slow internet.