I always assumed it's because 60 is a highly composite number (superior, in fact!). It's kinda the best number if you're ever going to need to divide. 50 is kinda garbage in that regard. :/
And PAL got a higher resolution thanks to it.
With 50 cycles/second you would need both divide-by-50 and divide-by-60.
here is a well animated video about it: https://www.youtube.com/watch?v=DyqjTZHRdRs&t=49s
So he can do exploratory electrical science and analysis with flexible cases?