I think that's a great question. I have always preferred a good cloth seat to leather. I suppose leather is easier to clean, but I can't think of any other meaningful advantages.
So if you worry about plastic pollution in the oceans et al. you should not want this either.
https://www.ecosourcellc.net/2019/08/08/microfiber-pollution...
https://ecophiles.com/2017/01/31/plasticfiberpollution/
https://www.patagonia.com/stories/an-update-on-microfiber-po...