Oh! It was not clear to me at first that this was non-read-only, though in hindsight I should have concluded as much from the phrase "see what the others are looking at and and [sic, whoops!] what changes they propose in real-time". Makes sense, thank you!
However, from the few times I've used VS Live Share, it has been helpful being able to join into someone's coding session and pair with their code directly. Both of us being able to highlight and tweak lines as we're talking did wonders to remove the "add x, no, sorry, not there, the next line/parameter/<item I referenced too vaguely>" or "show me y, now z, wait, go back to y" song and dance routines.
It's not necessarily a game changer for the way every person or team works, but as someone who has an easier time forming a mental model of everything happening when I'm "in" the code, there have been times I think it's saved a lot of back-and-forth compared to a traditional screen share.