You asking the wrong questions.
1. Why would a dirt poor Indian/Pakistani want UK/EU passports that allows them free travel through a continent with excellent social welfare and health care and where you can eventually bring over the rest of your family? The UK is breaking international law in that there is no legal way to claim asylum there so get an Irish passport first and you've won the jackpot!
2. Why would a native British person want a EU passport? Because the UK is a kip and about to get a lot worse! There's a huge amount of food & fuel poverty there and there'll be riots on the streets by Xmas, I'd predict.