It's always useful to have even if you don't need 8 worktrees with agents all going at the same time (I rarely have more than 2-3 active at a time). Typically there a tension between the 'fast way' (a big ol' slop branch bag of assorted changes) and the 'correct way' (carefully isolated branches and PRs) - with a smart implementation of worktrees like Conductor, the correct way becomes just as fast. That's basically the heart of good UX in my mind.