How live matters? There are a ton of social apps that use REST. You can fire refreshes on a timer, and on a pull down at the top of the feed. I can’t think of a single time new notes popped in live and it ever seemed “better” to me. 

And it’s more logic for client devs to keep scrolling positions right in many cases. 

There may be use cases outside the social “twitter clone” style where it really matters, but I’m with @Michael J on this one, having both options would be really nice for clients to have the choice. 

 but more options means more work for all relays, and doing database queries every second on behalf of a client that does constant polling for new events would kill a relay, while live subscriptions are simple and easy, the client doesn't have to update the scrolling, it can cache the live updates locally then display them when the user clicks or refreshes