But, why?

Like I said gut feeling. I suppose over time there may be some play in the axles, for example. Something feedback could compensate for but a rope could not.

Anyway good engineering requires extensive testing over many hours of movements.

	▲	jedimastert 2 days ago \| parent [-]
		> Anyway good engineering requires extensive testing over many hours of movements. He actually discussed this in an earlier video for his initial tests on the capstan drive. He ended up testing the rope he used for around 358 hours (two weeks) on continuous use in the drive itself with very low backlash https://www.aaedmusa.com/projects/capstandrive https://youtube.com/watch?v=MwIBTbumd1Q&t=10m