I use mine in my D&D games, as the DM. I don't use them often, but when I need to randomly determine what day of a month an event occurs, I use it.
I also have some d24's. I use these for determining which hour of the day a random event takes place. For example, if the PC's are rendered unconscious, I roll the d24 to see what time they wake up. Again, I don't use them often, but I do occasionally use them.
The OOP French boardgame, Formula De', used a d30 for determining how many spaces a Formula 1 race car moved each turn, when it was in 6th gear. The d30 was marked 21-30, rather than 1-30. That game used various polyhedra dice to generate how many spaces a car moved, in each of six gears. Each die was marked in numbers different than the number of faces, of course. The d4, for example, was marked 1-2, for 1st gear.
Each gear had a different movement range, which often spanned more than six spaces, covering gears one through six. It was a very smart application of polyhedra dice, IMO. But they were not standard polyhedra dice, either. I believe their successor racing game, Formula D, uses the same polyhedra dice scheme for speed in different gears, as well. Cheers!