How is this number "fairly low"? It supports every Windows and Mac PC, iOS, Android, Xbox, Quest VR and most major TVs and TV sticks. What exactly are you gaming on?
If you're out, on vacation or something, then sure streaming to your phone or tablet makes sense, but you're not going to sign in to a random Smart TV or PC with your Xbox account (at least Microsoft shouldn't encourage that behaviour). That just seems like such a limited use case to me.