Why do the Chinese top players use H3???

You will get the same effect with any high grip/tack topsheet rubber.  Try MX-S or Big Dipper.  EvenTenergy 05.  Racket speed is also critical here - the arc will be less with the new ball but you have to compensate with faster racket speed.  As someone pointed out, this might be causing some players to have more injuries.

With good contact on H3 with the harder sponges, it isn't so much the raw spin that is key, but the fact that you can continue to brush harder and harder with fairly thick contact and still get good spin.  If you have that kind of power and hand speed and hit the ball that way ALL the time, it helps but if not, you will be struggling when you only have the energy to flick the ball with the wrist and need to generate real spin. That's why I avoid going beyond 38 deg DHS or 50 deg Euro - beyond that, I know I will be struggling too much when I am too tired to play and can only use my wrist.

Actually, that is a property of heavy topspin balls, not tacky rubbers.  When a rubber is grippy and slow, it creates a heavy topspin ball naturally as it naturally imparts more spin than speed for a given stroke.  However, that means that a lot of the speed/power must come the stroke as opposed to the elasticity of the sponge/topsheet. So if you are a highly athletic ball bashing thick brush looper, tacky rubbers are for you (most CNT forehands).  But people with shorter movements  (most Euro forehands) aren't going to like them because of the demands for brushing and doing larger strokes fairly consistently.

Again, this is not magic - it's simple logic.

IMHO (& I may be wrong), but I'll think that they'll be blasting everything into the net. T05, with their stroke speed would occasionally bottom out.

AndySmith wrote: Put H3 (of any variety) onto a high level euro pro's blade and they would struggle to generate speed.

I don't know: this puppy (H3 Prov, 38 deg) was at day 8 here of the boosting cycle & still hadn't flattened (you should have seen it at days 2 & 3). I can tell you after putting it on that it felt a whole lot more powerful than T05 (which was on the other side).