If I ask somebody a question in person and they take 5 mins to respond then that's a pretty ling awkward silence. If I message somebody on Slack and they take 5 mins to respond then that's not unreasonable.
You could argue that the "Seen" feature of chat is meant to lower the acceptable wait time online, and indeed it does, but still not by as much. If somebody has "Seen" my message but doesn't reply after a couple mins, I'll start to wonder why, but usually my reasonableness kicks in and I think maybe they just are busy or didn't mean to click the notification or something. I'd still wait far longer for somebody to respond to a "seen" message than I would for somebody to respond to a "heard" question I asked them in person.
Depends what you mean by "interaction" though
In-person, people have a tendency towards politeness and waiting for the other party to finish their statement before making their next interaction. Computers are not accorded that grace.
I don't think it should be online/offline but more about the situation and the medium