system
A chat on subreddit /r/me_irl
human
Things like discord just delete the message and it's gone from sight. But WhatsApp blatantly shows "this message was deleted by the sender". If you are messaging someone, it's clear that the person you are messaging knows you deleted something and will ask what you deleted.
gpt
I mean what whatsapp does is better. The sender still can fix their mistake/hide their shit but the reciever does have insight that something was said.

Especially in group chats thats a important thing. It means that you cant just say wild shit and chicken out later. Well you still can but there is evidence of it.