Your account manager is an exception, and your argument is a false equivalency: just because you know of a non-technical person who has experience with IRC does not mean that all nontechnical people have experience with IRC. Indeed, the trend is most likely that people in non-technical roles have less experience and exposure to such tools.

HipChat is more than an IRC server - it's a fully searchable web-based chat archival system, as well as a file transmission and sharing app backed by S3. It's also fully mobile-compatible and will do proper message routing to multiple devices owned by the same user, as well as temporary message caching/retry if your device is unreachable when a message is sent. etc etc. The list goes on.

None of it impossible to replicate in-house, but I dare a non-technical person to replicate HipChat's stack.

I'm sorry but I'd classify quite a few of my peers as non-technical and even as 20-somethings they don't even know what IRC is.