I think it's mostly a made up scam between the girl and the bar. However, the girl could owe the bar money from a loan or whatever and the bar wants to get repaid.
Phi Phi is more expensive than Phuket. Little to do there and the restaurants are not so good. I was there in Aug 2024 and the place was packed. I won't be going back.
Giving people benefits is the same as asking them to come. There is no deterrent to this invasion. The current UK gov't is hopeless and complicit. The past gov'ts were similar.