I would like this for sure. But there is also the situation where you might want a folder to not be indexed by Obsidian. I have a few reference library folders that I never add to or change but often have to wait while Obsidian heats up for a minute or two when I boot the vault up. Sorry if this is unrelated. Maybe I should do a feature request.
+1, would be useful to hide Attachments, Templates and Databases (used for DataView data) folders.
I feel it would be convenient to toggle whether or not these hidden folders should still be accessible via Open File (cmd+O)
Yet another +1 for this. Vault is getting too big with all other external documents included in it, and search is basically unusable at this point. This is becoming quite mission-critical XD . Being able to exclude certain folders/control the scopes is key to be able to continue scaling effectively with ever-growing vaults