Just shows how desperate Trump is for legal representation right now. This is just another example of Trump hiring a friend/celebrity to fill a role on his reality show. The only thing Trump respects more than unyielding loyalty is celebrity. Rudy brings both. It's like the late stages of a long running sit com where they add a new main character before finally canceling the show that they should have canceled two seasons ago.
And from Rudy's introductory ass-kissing of both Mueller and Trump, I suspect he's not being brought on board for his robust legal mind. It's to hopefully broker a deal that ends this investigation. If you want someone to masturbate about 9/11, he's your guy. Anything else is all creation, he's useless. Not to mention, he was a recipient of leaks of the DNC emails. Nothing like having a co-conspirator on your defense team.