Yes I replace antique desk fans with capacitors, I'm in the process of buying more capacitors.
I think they run cooler. Not too difficult to verify results.
Plenty of technical information out there. Nice to see 100 year old fans running. You can hear how the Eddy to currents react with different value capacitors.
I have noticed that with the original autotransformer the fan feels a lot warmer. An without it runs at full speed an stays cooler etc.
These things are very old. Nice to look at an demonstrate but might need more safety.