I have been advised today by ASDA that this issue was passed on to the relevant department “so we can review the possibility of introducing this payment method to our stores”
I doubt there is the same motivation to get this up and running in the UK as there was in the US, but if I hear any developments regarding a Walmart Pay UK or an ASDA Pay I will keep you posted.
What would be the point of it though, with ASDA not having a loyalty system?
I use the Tesco one, but only because it automatically adds clubcard points to my account and sometimes adds extra bonus points…
For them it would probably reduce their merchant banking charges.
Assuming anyone cares to use it, which nobody will. MCX (aka Walmart Pay) is the proof. 
Surely they must have to give some sort of incentive to the user, I can’t see everyone flocking to use an app in order to save ASDA bank charges!!