You can send money in messenger. Not too hard to move from P2P payments to P2B payments.
The interface to that service was extremely crude by today's standards (basically a set of magic keywords that comprised a simple query language), but people liked the convenience so much they were more than willing how to talk to the bot in its own lingo. I can only imagine how much more popular it would have been if it had a real, natural-language chat interface.
As long as it's easy and convenient, and comes back with the right answers (a big if, that last one), nobody will care if there's a human on the other end or not.
Reminds me also of an observation that a lot of people in accounting are actually programming without realizing it, by virtue of making pretty complex Excel spreadsheets to automate their work.
It's funny how much of users' apparent inability to grok computers is actually in their heads. Also, the fetishization of GUIs that has been going on for the past two decades is actually quite sad - it robs people of efficiency and convenience in using the machine.
I was all over IMified & ActiveBuddy when they came out 10-15 years ago but they never really took off at all. My agent basically returned the Google "magic box" which was kinda cool.