[fundamental]

'Hello' as a method of establishing a synchronous chat makes sense, but if you just need an answer to a question when someone reads through chat next, then it's by no means a required formality. My personal stance is when a discussion can be asynchronous, let it stay that way.

[asxd]

Exactly, it can be polite to check if someone is ready to chat synchronously, but doesn't make much sense otherwise.

[wpm]

I picked up sending a "ping" to folks I need a back-and-forth with from one of the people I work with.

[fellowniusmonk]

Agree, saying hello is an anti-pattern in async communication for existing teams.