He is technical enough for the role he will play. He provides variety and other qualities to complete the squad imo. Also age is a positive, you need experience especially with all the youth entering the club.
Outdated "experience" from players who weren't performing at their best level for years is a big part of what sunk us in CL play the last few years. Suarez, Rakitic, and even Iniesta had been resting on their laurels for a while without actually backing it up in performance at the tournament level for us. Vidal is another player well past his prime hanging onto the same.
We need invigorated, hungry youth that is talented enough to compete for starting spots as early as possible and gives a fresh take on this team and its playing style. Only through real change in our identity will our fortunes in the CL change too. Arthur, Dembele/Malcom, Semedo, etc. are key additions to blood early and shake things up in our core team. Vidal/Paulinho are not good enough to make any notable impact and gives us more of the same.
Do you think the policy that won RM 4 CL's in 5 years was loading up on washed up workhorses and technically limited starters? No, not even close. They bought several talented youngsters (a number of which have succeeded greatly) and made sure everyone in the starting lineup is at the technical level required for their role.