In my experience, since Messenger / Hangouts / etc all support persisted, named chats, people start treating them like chatrooms rather than like text messages. I don't want notifications for a chat room (where there's a flurry of conversation that may or may not be directed at me), and in general since I work remote I try to keep the "things that make my phone buzz" list to the bare-minimum, since that list will always include "production outage" which might make me stop mid-step while heading to lunch and turn back around.

Additionally, FB messenger does not allow you to disable "read receipts," it always shows the other party when you have opened a message. Buzzing my pocket and then telling the other person I read their message feels very intrusive to me.