Example 2 sounds like a pretty big pain if I can't go directly from Bob's chat account to his document account. Which is the case the vast majority of the time.
And yet somehow you managed to log in to this site to post this comment here despite needing to log in. Crazy huh, I would have thought it would have been a pretty big pain.
Or are you saying its a pain for you, Eve, not being able to see Bob's documents so easily?
The problem isn't logging in. It's trying to figure out what account to share access to. For a pretty straightforward analogy, I have never had to figure out somebody's steam handle in order to reply to them on HN.
And when I'm replying to someone on HN, I never have to worry "do they have an HN account already?".
Or are you saying its a pain for you, Eve, not being able to see Bob's documents so easily?