Twenty years ago I don't remember playing at many, well any, courts that had significant grit. They were all fairly slick and had very, very small grains of sand mixed in the top paint. That or the courts were just old. As I think back I did not care much about court surfaces or other uncontrollable variables.
In the last 2 years, I've played at over 20 different outdoor hard court locations. All the resurfaced ones are just beautiful. But when I bend down and run my hand over the court surface it's really sandy and rough like sand paper. Maybe more sand, bigger sand brings less liability for the court owners? Less slippage in light rain?
As for the courts that had not been resurfaced recently most still seemed pretty slow. Again lots of big sand particles in the paint. Somehow I get excited whenever I see a court that has fairly smooth paint with little sand. Balls move faster, when running I don't stop as abruptly, and balls fluff up less.
Courts with more sand (or larger particles) seem to bring advantage to spinny strokes. Kick serves REALLY kick, topspin loopers really dig into the rough surface and accentuate the spin by popping the ball high.
Prince EXO3 Tour 18x20, 12.5oz, 8HL, nat gut strung too high, S&V, D2 '88-90