I have been sitting on a zafu for roughly 30 years. My knees finally complained enough that I now have to sit in a chair.
Actually the chair is significantly more comfortable and results in a much straighter spine. The effect of meditating in the chair seems to me to be significantly better than sitting on a little pillow.
Which led me to notice that Buddhism is related to social behavior more than 2500 years old. That was long before the chair was invented. Chairs are still not used in much of the world. Africans for example and much of Arabia live without chairs in their homes.
It would be very hard to say sitting in the traditional posture was somehow better than sitting in a chair because the comparison was never made by the people who primarily developed the meditating sitting posture known as Lotus.
I point this out primarily because patterns become traditions become religions become orthodoxy. I am particularly interested in what it is prominent in the industrial commercial world that needs updating.
I actually think a good chair is better than a zafu.