Oh, get off your high horse

Your basic unit for speed is m/s, but for most day-to-day purposes you use km/hr. The conversion between the two isn't even an integer!

Not only that, but your system, by virtue of being decimal, inherits all the shortcomings of our quite flawed numbering system. You can't divide something by the second smallest prime number without breaking out repeating decimals.

In my opinion, a good measuring system would make up for those shortcomings instead. It should be divisible by at least the numbers you can count on one hand. Decimal covers 2 and 5, so ideally the measurement unit would cover 3 and 4. So that would be a base 12 system. Technically 4, being 2², would be covered too, so 3 would do just fine. Ta-da! 12 inches in a foot, 3 feet in a yard.

My ideal would be 21 though, get that 7 factor

If you like intervals of 1000, you'll be delighted (or mortified like me) to know that 7×11×13 is almost exactly 1000 (it's 1001)

I use both in my wood shop. Sometimes it's easier to lay things out in metric or divide numbers, but other times it's easier to remember an imperial number to go make a cut.

Imagine being so close minded and bad at math that you can only think in base 10 and feel the constant need to degrade people who are good at math in different bases

And to remember the number of yards in a mile: 1 San Francisco

One-seven-six-oh

What about a nautical mile?

I wish we had a metric inch because the fuzziness can be useful.
"How small do you need these veggies diced?"
"2.5cm ish" vs. "about an inch"

I feel like the implied margin of error is much larger for inches, which make them useful for many things where precision isn't necessarily desirable (hemming, wargaming, moving furniture, etc..). If I'm wargaming having a limit on rounding is useful (half an inch - either round up or down), assuming I'm playing at a scale that uses inches.

Feet I have no use for, with one exception - adult human height between 5' 2" and 6' 2". There I find metric too precise (whereas to the nearest inch accounts for variance in sole thickness, hair volume, etc.).

I wasn't raised on imperial (and I'm baffled that people younger than me in the UK still talk about stones. Sixteen stone is fat, sure, but I've no idea how fat if not told in kilos) but I find inches to have their uses.

Also miles for cars - because common speeds are ~60 and ~30 mph so a road sign effectively gives the time to arrival (e.g. 13 miles on a motorway = about 13 minutes). I don't use them for actually measuring distance on a map but they're handy when driving.

I hate to point this out, and will likely be shunned for it - but it is base 12 and kinda easier.

So whose foot exactly?

Metric is used all around the world, but comes from a quarter of it.