Was incredibly popular a decade ago. Very few organisations still use it, and almost exclusively it's for legacy reasons. Nobody buys it today.

Probably they work(ed) with extremely large organizations or anything government, Cisco is very popular for telephony there and when you're already using their hardware gear you might just as well go and use Webex because it perfectly interfaces with their phone and conference room system.

I'm not doubting you, but I've only ever seen it once and don't know anyone that says they use it regularly.