CSS 3 defines pixels that way (1/96 inch, pt is 1/72 inch), but the previous definition was rather different, and had no fixed relation to either inches or ems.
But I thought the change in CSS 3 was because pretty much every actual implementation of CSS 2.1 had taken the definition, chucked it out the window, and used 1/96 inch anyway. So, I don't see how any problems could arise in practice from using px instead of pt.
CSS 3 defines pixels that way (1/96 inch, pt is 1/72 inch), but the previous definition was rather different, and had no fixed relation to either inches or ems.
But I thought the change in CSS 3 was because pretty much every actual implementation of CSS 2.1 had taken the definition, chucked it out the window, and used 1/96 inch anyway. So, I don't see how any problems could arise in practice from using px instead of pt.