it's a little better...
The match trigger kit comes with a lower rated hammer spring, so the trigger pull will be noticeably better. It also comes with a new weaker reset spring. The net result of this is that the trigger pull is really good, I'd guesstimate 8.75 - 9 pounds DA. My experience however was that the weaker trigger return spring cause the reset to be just plain lethargic. I put the stock trigger return spring back, and the reset was back to normal, and trigger pull was still vastly improved.
The "length" of pull won't change unless you have a really old USP which only has the "single stage", no 'half cock' hammer. Then when you decock with the lever, the hammer falls to the 1/2 cock. However, the match trigger does come with an adjustable overtravel set screw. This will somewhat reduce the length of overtravel... I did not have good luck with this, as the trigger breaks just a hair differently each time, and, the set screw backs out- loctite any color notwithstanding. I ended up cranking the set screw all the way in forgetting about it. When the set screw backs out, the gun won't fire... a bad thing.
No, the trigger doesn't "get better with use". The user gets accustomed to it. No doubt, someone will dispute this with scientifically proven 1st hand experience...
Just keep the contact & moving parts well lubed, dry fire often, and shoot often.
Is the match kit worth it ? It's a bit pricey. Doesn't Wolff make replacemetn hammer springs ? If so, that's a much more economical route.
If they ever get around to refitting the LEM trigger to full size USP's I'm there...