Google's help pages, which I'd started reading through, make it sound as if the Google+ profile exists separate from this other access. But I've now seen enough such "WTF I'm blocked -- from everything!" stories to make me very hesitant.
I've thought of making a new account to use with Plus, but there is also some buzz going around that makes it appear Google has coincidentally become more aggressive about pursuing and blocking "duplicate accounts". Again, anecdotes, but worrying.
1) Not just Google+ profile dependent activity, but Gmail, Calendar, Docs, etc.