As always it pays to read the smallprint. And again the people who lease will not be concerned by extended periods of warranty, but for buying owners and more likely secondhand purchasers it could be of importance as to their decision making. Would/ could it be retrospective to 2022 buyers.
The main reason I ask is that I just watched a YT video for a "relatively simple" repair to a Renault Zoe which had it been better designed would be economical to achieve but requires massive dismantling just to reach the offending part , making in effect it almost an economically scrap car which if fixed has many years left in it. This of course had it been a MG would have just fallen outside the 7 year period of warranty leaving the owner to carry the bill for a 300 pound part with a possible 6000 pound price tag " or more ". This was an independents bill not Renaults which potentially was double almost certainly scrapping a 8 year old car.
Even if it was just drivetrain related, Motor, Battery, Electronic components that make it work as a car, then that would be a peace of mind to owners, and if MG are confident of their products reliability a selling point for the brand. ( although there are some pages on this forum which would reliably dispute this .) did I mention , smallprint .