pull down to refresh

OP_RETURN is mostly used when you want to send a message to everybody, publicly readable on a blockchain explorer.
For example you can even send an anonymous message on the blockchain with this LN bot https://opreturnbot.com/
Signing a a message using a wallet app and a BTC address is different, you send a message to a specific user to read it and you prove that you are the owner of that address.
Are two different things. But is an interesting question indeed.