Hong Kong is a bit jumpy about people hooking up online, precisely because there's so much of it going on, paid and unpaid. As a consequence it's difficult to discuss it on this forum (which is after all dedicated to paid sex) without crossing the line and getting the thread shut down.
There's no doubt you can succeed, you can. 'Nuff said
The bigger question is: is it worth it?
Those sites typically have 5:1 more men than women registered, so by definition fewer than 20% of the guys will be getting some. That means you have to work harder than 80% of the other guys to get noticed and move forward. Can it be done? Sure. But ...
It's always going to be easier to browse this site, pick a cute photo, and walk up to her door. Faster. Full and immediate gratification. You know she won't say no, need another dance, another drink, or phone you afterwards. And in most cases it costs a lot less money.
But if you enjoy the thrill of the chase, if you enjoy beating out a hundred other guys who are trying to get what you just got, you can most definitely get "free" sex ... plenty of girls are looking for exactly what the guys are looking for ...
In many ways it's a good "acid test" to make sure you are on your game. CAN you beat out 100 other guys without trying too hard? Just remember to keep count of what it's costing you in time effort and money, and keep it all in perspective!