Raw packets? Legacy? Have you've ever talked to anything over a socket?

You don't need a raw socket to get into trouble. You also don't need a "legacy" protocol.

Yes, plenty of times. But I’m usually using raw byte arrays via protobuf or something similar. ASCII only text protocols are rare. Most devs don’t reimplement them from scratch.

I’d wager most code is application code, where UTF8 strings are a great choice.