"Why do they do it and why don’t we walk?"
Simple economics. A quick look at VS for the West Midlands shows 108 independent Asian adverts.
Take off 50% for duplicates, old ads, Thai's and the odd mis-placed massage ad and it still leaves over 50 possible locations.
The pictures are there to lure in the gullible. The services offered are usually pretty vanilla but at a price point that many can afford.
I have had bad and good punts but I don't think there is any difference between expectations with Chinese or Roms.
Punters are looking for a fuck and sometimes it is easier to go through with the meet rather than look elsewhere. Especially if you have dosed yourself up with the anticipation of emptying your balls.
Definitely pot luck but I have followed up a 30 minute meet with an hour return visit when I find the odd one that floats my boat.
Probably the best advice I could give, if you have concerns, is don't use VS. Bit like the TV, there are other channels available.