Babylonians were obsessed with divisibility, so they went with a base 60 system. That’s why we still have 60 minutes 60 and seconds. Also the 360 degrees of a circle fits that ideology, because 6*60=360.

I like hexadecimal because since it's (2^2)^2 so it works with computers pretty well. 2^2 is too few symbols, it would make writing numbers unnecessarily long. And ((2^2)^2)^2 is too many symbols to easily memorize.

Years and days are fundamental units that you're kind of stuck with because they're so fundamental to life on earth. But, even though seconds are SI units, there's nothing about them that's special. They're just a holdover from dividing a day into 24 units, then those units further subdivided by 60 and then another 60.

What's interesting is that the metric system was invented at a time when being able to convert between units in a way that's easy for the human brain was important because technology was advanced enough that things could be measured precisely, but wasn't advanced enough that computers could do the conversion for you.

What's interesting is that now, before Metric has even caught on worldwide, we're already past the point of needing easy conversions. The Metric System was important when it was invented because technology had advanced to a point where precision measurement was possible and important, but computers didn't yet exist. So, converting between miles per hour and feed per second was a pain. But, these days everyone has a smart phone, smart watch, voice assistant, etc. nearby that can easily do the most gnarly conversions with ease.

I'd still like metric time units, but tradition might win over logic now that Apple Watches are so common.

I feel like the time thing is less an issue than other systems because it’s better adopted across the world. Part of where metrication came from is that each country would have their own standard for how long a foot or how big a gallon was, but the months, weeks, days, hours, minutes and seconds are pretty well agreed these days. Most units can be selected arbitrarily without changing much about their usefulness, but with time you want to stick as close as possible to solar days, number of solar days per year, and maybe line up with some seasons/solstices/equinoxes. Changing the sub-divisions of the day also means we’d probably want to re-draw time zones, so we’d want a subdivision that can be reasonably easily divided by something close to 24. I guess you could have a 10 hour day and each hour be 100 minutes, or some such and move to 20 or 25 time zones to keep relatively consistent. A 10 day week doesn’t divide evenly into a year though. The divisors of 365 are 73 and 5, so I guess you could do 10 and have one of the weeks split somewhere, but then you still have to deal with the occasional leap year.

Then there’s the consistency issue, the length of a day varies over time, so regardless of the subdivisions we choose, high precision measurements are going to need to account for that to keep our time in line with the solar day.

Decimal time was used for longer workweeks like 7/10, which is counter-productive both in the literal sense and popularity-wise. I wouldn't adopt a time system that robs me of break days and for all I know 4-day workweek is actually more productive societally.