I’m afraid my knowledge about the Stable branch is fairly limited, but I think it’s geared more towards not changing things very often. So I would think adding new plugins and extras outside of a Stable release window would be counter-intuitive to that?
It’s also worth saying that most Discourse sites use tests-passed and generally don’t have any notable issues. Even following test-passed doesn’t mean you need to update every day though and be on the very latest version, so it’s not as changeable as you may think. You would manually have to press the update button from your /upgrade page, or perform a rebuild, to pull those changes into your site.
Managed hosting also makes this process easier too as an alternative, as they’ll handle all of the technical stuff and let you concentrate on your community. 