I used an alias to create a Google play store account to sign in and download all the apps I need. I then set up a separate profile for just Google items, Gmail and Youtube (I understand that play services and the app store are needed almost everywhere for some apps to run correctly, done that).
In this "Google app" profile I can open youtube and watch a video while not signed in. I was wondering if I signed in using my actual Google/youtube account if this sign in sees the other alias account in my Owner profile and conflict in some way. I don't know how much sandboxing prevents this or if my device would show up at Google as already signed in someplace and cause problems.
This isn't a critical feature but it would be a nice to have if I wanted to access Youtube content and possibly Gmail from a dedicated profile without polluting everything else. If I have to choose between using an alias and my real google account I'll probably just stick with the alias and forego google products on the phone.