I'm probably not the target audience since I actually really like Git's command line tooling, but…
Basically what gets me very interested in smerge is the potential for it to drive a three-way merge with SublimeText's syntax highlighting and keybinds. Literally, I want to be able to use it as the editor that I have set for
git config --global merge.tool. Unfortunately, as per @jps's comment from earlier, it appears this isn't possible.
So consider that feature requested! That alone would be worth me paying money, and that's probably the only feature I would care about. Beyond that, this is shiny and cool, but doesn't actually help me (especially without worktree support, but even with worktrees, I'd probably just stick to the command line).