I think it's absolutely sensible.
We've been wanting it in Walton for years. The centre of Walton is an island bounded by High STreet, Hepworth Way/Bridge STreet and New-Zealand Avenue. Churchfield and Winchester roads are rat runs that empty into the high street because the high street traffic lights tend to cause tail backs..
Closing and pedestrianising high street would encourage more of the closed retail to convert to restaurants as there would be lots of frontage for pavement cafes, more trees and planters. It would be safer for the primary school kids heading to the school at the foot of the high street. Traffic would be largely unaffected. As it is, the high street is run down and depressing. The only issue would be the deliveroo riders getting to McDonalds and Burger King - but guess what. Instead of illegally dumping their mopeds on the pavement, they could collect from the service carpark behind each of those establishments.
We also know it works because the high street is closed off several times per year for events.