Actually, at work, I'm either in 2 situations:
- I need a quick answer for a simple problem ==> chat (because it's more about getting a simple info and I need it now if possible, or the sooner)
- I need a complete/correct/thoughtfull answer ==> email (because I need someone to really think about it before answering and that person is not available all the time and has other things to do too... so quality of answer is worth waiting)
It may happen that complex email need some clarifications... but if the subject is complex, it usually requires a meeting
It may happen too that a simple answer lead to a complex question... but then we're back at email.
So, I'm not sure that your tool would fit my way of working and/or the places I work for. Moreover, I'm quite sure that "realtime" is one of the WORST possible way of working because it's giving other people a way to manage your time at work (interrupting, etc.)