I tried Orion about a year ago. I tried using the profile sandboxing. Logging into my google account in one profile also logged me in in another profile.
I can definitely excuse some bugs (there were crashes for example that I didn’t overly mind; I understand I was using prerelease software). But something like account containers should be built fundamentally to disallow any data sharing. If data sharing is a bug, and not fundamentally disallowed by the architecture, then it’s going to happen again later.
So for that reason I’m not bullish on orion.
I'd be interested if the issue you ran into was actually due to poor architecture or just something not fully implemented in the pre-release. Unfortunately, it's closed source - so hard to tell from the outside.