Good value signing. Also, as Prezlke mentions in the OP, it would have an added bonus of not being held over a barrel with the negotiations over Walker, or another fullback for that matter. We could walk away if the price got exorbitant.
As seen in the CL semis and his performances in Serie A this year, he still is marauding up and down the right flank like he was a decade ago. Age is a relevant perspective to an individual and maybe his 34 is another mans 30. Certainly, he'd be good for the upcoming season at least, if not the subsequent season. Buys us time. The chances of getting three or four young full backs who could potentially with us for the next 5/6/7 years this window are slim. He had experience in abundance and I dare say could slot into the inverted fill back role Pep prefers. We know he won't be here for a long time but at the price quoted, it's good value.
Also, as with Vieira, you can't have too many guys like him, in and around the club, the dressing room and the training pitch. The experience and inspiration he could pass onto the young lads in the Academy, regardless of their position, would be invaluable
I would not be disappointed to sign him