The signal of using signal for running the business is that by working there you’re likely committing a crime every day by working there. If you’re not DJT’s bff, or when Elon gets kicked out of cool kids club, you’re boned.
So the fact that they think it's a good idea to just start a bunch of chats on Signal should be surprising, but it's Trump and Elon, so I guess it's just another thing in a long list of insane things that just happen, and we just kind of ignore them and pretend that everything is fine.