My guess is that, given that the service they provide is just burning money because it is effectively subsidized by investors, they seek to do the platform play and go for good-old lock-in, in order to have monetization leverage in the future. We will see how it works out. In the background there is this tug of war between self-hosted models and centralized services, the type of battle we have seen many times before. More times than not the centralized services won, at-least initially, than not for various reasons. If i would have to argue for the self-hosting part is that these days, there is a lot of ''ecosystem-potential'' for the decentralized camp, of which Nostr is an element in that equation. A big risk for the centralized camp is that as soon as their models don't show drastic improvements over the iterations, odds are ''free/open'' models will catch up and reach parity soon enough, at which point the only edge they have is economies of scale in terms of competing over what is ultimately just commodity hardware.