For example, I need multiple spaces where each space is "dedicated" to a single Google account -- it has multiple tabs open that are logged into that particular Google account.
I tried to create that setup, but the accounts "leak" between spaces: logging into a Google account in one space doesn't allow tabs in other spaces to be logged into a different Google account.
If you ever implement proper account isolation per space, please notify me: I'd like to be a beta tester.