It’s a tiny ass island yet whenever a British person hears another British person they’ll be like “Oi guvenor! I know exactly where in Merry-ol-England they are from! Clearly they’re from Bovinshire-upon-Weavilton!” And Bovinshire-upon-Weavilton is a town like 10 minutes away from where they live.
Regional accents are good.
They connect people to a history, the landscape and the world around them. They’re basically the only non-toxic and commonly accepted form of identity politics a lot of British people have, on of the last threads connecting people beyond culture war bullshit. They’re the primary way most people ever hear or think about working class history and pride (in a non made up tabloid way).
Also, they make the language interesting with lots of regional words and idioms plus lots of them sound funny or nice.