Every clean rider has weaknesses. Ving hasn't shown any weaknesses yet except maybe the cobbles and an inability to sprint with Pog. However, Vingegaard must have some weaknesses beyond those. He's only been an elite rider for what, 2 years? I am not sure he's been figured out yet.
What does that have to do with Vine? If UAE is serious about being Jumbo and Ving at the Tour, they need a team with 2 riders for the flat/hills. Let's say Bjerg and Wellens. Then Pog's spot. Now you have 5 riders left. If you want to win the Tour you bring Yates to counter Primoz either as a GC decoy or a super domestique. Then you bring Brandon McNulty, Ayuso and Majka as more domestiques. That leaves 1 spot for someone from the Soler, Bennett, Formolo, Groschartner and yes, Vine group. That also leaves some talent to go for the Giro which UAE seems intent to do.
Is Vine needed? No but UAE needs depth. I find it curious that we didn't get the signing until after the Tour route came out with no TTT and a lot of climbing. UAE has the team necessary to pull back Roglic attacks and possibly even Ving, if Ving is human.
So I like the move, it's another depth signing and yes, I could see an in-form Vine pulling back some attacks in the third week of the Tour even as the 8th rider on the squad. They have created a team for the 2023 route, that's for sure. Now the question is just how beatable Ving is and how much was his machine like performance from this year's Tour an aberration.