Leather against your skin? Ew. I put up with animal skin seats in cars because they are durable and easier to clean than cloth, especially with kids. But I much prefer soft fuzzy fabric touching my skin than hot sticky leather. There's a reason people don't wear leather underwear!
Sorry I just don't get luxury car buyers' leather fetish. Tesla's synthetics are more or less the same as leather, except better for the environment. A high quality fabric would be even better (well, after my kids are old enough to stop putting shoe prints all over!)