I originally got M10 x 1 for the small CM-6 spark plugs often found on models and have slowly built up a collection of the fine metric threads M4 & 5×0.5, M5x0.5, M6, 7 & 8×0.75, M8, 10, 12 & 18 x 1. They mostly get use for steam fittings, glands etc on the models I deign which are all metric.
The 1mm constant pitch is not far off the old 26tpi which was also an ideal thread where something finer was needed and 0.75mm pitch is close to 32tpi ME but the 0.5 is a bit fine once you get above M5