I see the point, and I would move in that direction if I did not feel that what I am missing from Obsidian (so far) is only a very tiny feature.
All right, it is clearer to me what you are looking for. I wasn’t sure if you were looking for alternative shortcuts for formatting, which I think that particular script is better for, or a much broader suite of typing aides.
The notion of being able to select text and hit a punctuation mark to surround it, instead of replacing the selection—in and of itself is something I definitely do have on our list for consideration, because that’s not even something we just get requests for from Markdown writers. Every kind of writer could benefit from being able to easily make a selected phrase within a sentence a parenthetical, or to mark off quotes around text, or even to auto-complete these pairs as you type forward. Having a field somewhere in settings where you can type in punctuation you want to use as pairs makes good sense to me.
As to the larger topic of using two programs together on the same data, I was thinking more broadly of the many things Markdown plugins and software do to speed up typing and auto-complete, and comfortable it is for extended writing sessions in them. For example, I make heavy use of the listing tools in my editor, which number lines for me, make bulk nesting operations a snap. There are dozens of things I use of that nature, on top of the one you describe where selecting text and hitting certain forms of punctuation will surround the selection in that pair.
Once you do have something like this set up, it’s extremely low overhead, at least in my experience. It is little different than switching back and forth between the binder and the editor, you just punch a “sync now” shortcut now and then when switching between the two.
Again, I personally wouldn’t pair Obsidian with Scrivener in this way, for that purpose, as I don’t find Obsidian’s editor to be that much of an improvement—but it would certainly work well for that. For myself, it is not just the Markdown typing aids I miss in Scrivener, it’s the extensive raw text editing features that special-purpose text editors have a bounty of.
Hmm, well one small little trick for this that works just about anywhere, that is better than manually positioning the cursor before and after the range of text, is to select it as you would, then cut, punctuate, paste, punctuate.