Dell claimed that physical keyboard is too thick to put in enough cooling for 28W Alder Lake-P chip in thin-and-light form factor. The touchbar is much thinner allowing more room for the heat spreader.

Having seen benchmark number from XPS 13 Plus compared with other notebook equipped with Alder Lake-P, it looks like it's working.

Maybe for vi users, on GUI based OSes it mostly boils down to dismissing dialog windows.