Salt participates in chemical reactions of cooking beyond just being salty. You do notice in other ways.
I know someone who had to go on a salt-free diet for a while. She said that she once broke down crying because of how bland everything tastes.
My wife also has an aunt who's doctor told her to cut back on salt. She interpreted that as no salt, ever. You can always tell what dish she brought to dinner.
Right, and it's sort of a historical quirk, as well. You always need to compare your speed to what came before. That logic stretches back to computers that did not use 8 bits per byte, but still communicated over various channels to other computers.
And then there's just plain marketing. Not just that it makes the number 8 times higher, but that any one ISP that chose to advertise in MBps rather than Mbps would suddenly look like they're slower. It needs to be mandated for everyone as a regulatory rule or it just won't work at all.