Thank you, it is still a little odd that the message is removed for both parties if one party deletes it.  Traditionally messages work like email, if the sender deletes it, the message is still on the receivers system. 

I would prefer this to be the default for messenger, as it is how WhatsApp, Viber, Signal and Telegraph work and it would mean less user education.

I do like the function to delete the messages on both sides, that could create Snapchat styled features later.