Though many of their competing apps support this feature. Facebook, Apple, WeChat, etc.
But everyone wants to send money or money-equivalents. I use Venmo almost every other day.
But why roll that in to a chat app? Why not use your bank's app (or if you live in a country with a 19th century banking system like the USA, something like Venmo)?
I guess because your chat app is also your contacts management app, even if by accident.
Because I have performed out of band verification for contacts in my chat app.