Retail customer support is one such use-case. In the Netherlands, national railway company, many banks, telecoms, etc - all have webchat/twitter dm/whatsapp contact options prominently displayed either alongside phone numbers or replacing them altogether:
If you’re interacting with a human, I’ll argue that synchronous messaging is the most efficient and comfortable way to communicate. Imagine how much faster customer service problems are to solve that way than with a ticketing system, email, or phone (where you have to wait on hold and one operator can only help one person at a time).
The biggest advantage of messenger apps is that they're both synchronous and asynchronous, depending on the client and user behaviour. I'm working at a place that builds a customer service platform based on connecting messenger apps to a web client for agents to work in. The speedup you notice compared to Callcenter agents is astounding - they can handle multiple cases simultaneously, without having to wait for individual customers. They, in turn, can respond whenever they like to. It's really cool!
Wait for Boeing to announce new pilot UX - no more that stupid screens, just chat bot.
It's the most used form of interaction. Text messaging.
Messaging : communication. Basically meaning not visual Ui. Communicate it and it is done. Input interface specific.