they really only work when the city is under 2 to 4 mil. Anything beyond that. its' a waste of time. You will just get hookers. or Massive time wasters. seems interested and thennnnnn she's not. kinda thing.
in big cities these girls are BOMBARDED with "fuck me/pick me" messages all day long.
To a point unless you are god like good looking. Even an amazing sense of humor won't do it, cause you wont' keep her attention long enough for it to matter.
small cities i would use dating apps. Since cold approach is less often due to less people. But tokyo or jakarta or manila ( i think its' 8 or 10 mil big). forgettaboutit.