That is indeed something I have jotted down on our list of improvements to look into. It would probably be possible given we already do something very similar when typing <$..., which is the syntax used by Scrivener’s placeholders.
Obsidian is a good tool, but I find it useful for an entirely different kind of thing than what Scrivener provides. The two even work quite well together if you want to press the advantage of those areas where they don’t overlap.