Probably because the 'logic' often times is dependent upon the technology at the time of their origination. Horses use to be measured in hands....literally. Why? Obviously, because it was, on average, accurate enough and the measurements weren't dependent on accuracy, and even if it were they didn't have the fine scales to measure them with anyway. We don't use that measure anymore......there are far more reliable and repeatable ways to do that.
Back when the English units were devised, apparently it was thought it to be the most 'logical' at the time....base ten number system since we have ten fingers and ten toes.
As technology advanced the English system has gotten clunky and cumbersome. As a scientist I wish they'd go to all metric in the USA too, but people here just don't want to do anything related to 'brain' work. So there is great resistance. I think the metric units should show up along side the English units for a period of 3 - 5 years and then drop the English units altogether.
As for time.....you will always gave to make adjustments for various location on the globe, so you use gmt - 4, or gmt + 5....whatever, you still have to remember if it's forward, or backward, and by how much. That convention really isn't any better than any other. See, I regard that like most of those hoaky memory courses where...in order to remember your new insurance salesman's name you have to remember 10 (whatever) other things instead. He wore a gray suit, so you picture an elephant at your door.....he had a beard so you have to imagine a pirate say......he was tall, so you think of a basketball player....and on and on. It's a common memory scheme that people think is great, but I happen to think it's idiotic. If you can remember those 10 things, then why can't you just remember the two....his name and number......yanno?
As far as the clock....that's so inconsequential that it's really pointless to mention. It's just a clock, most of it is by context. The 5 seconds you save designating 17 hundred hours without explanation of am/pm isn't really going to make you or break you....is it? Logic is fine and good if it's really worth while for daily life type stuff.