> setting weights and measures by local and trade tradition and it was a nightmare

Adding to your point, it is human nature to create industry- or context-specific units and refuse to play with others.

In the non-metric world, I see examples like: Paper publishing uses points (1/72 inch), metal machinists use thousands of an inch, woodworkers use feet and inches and binary fractions, land surveyors use decimal feet (unusual!), waist circumference is in inches, body height is in feet and inches, but you buy fabric by the yard, airplane altitudes are in hundreds to tens of thousands of feet instead of decimal miles. Crude oil is traded in barrels but gasoline is dispensed in gallons. Everyone thinks their usage of units and numbers is intuitive and optimal, and everyone refuses to change.

In the metric(ish) world, I still see many tensions. The micron is a common alternate name for the micrometre, yet why don't we have a millin or nanon or picon? The solution is to eliminate the micron. I've seen the angstrom (0.1 nm) in spectroscopy and in the discussion of CPU transistor sizes, yet it diverts attention away from the picometre. The bar (100 kPa) is popular in talking about things like tire pressure because it's nearly 1 atmosphere. The mmHg is a unit of pressure that sounds metric but is not; the correct unit is pascal. No one in astronomy uses mega/giga/tera/peta/etc.-metres; instead they use AU and parsec and (thousand, million, billion) light-years. Particle physics use eV/keV/MeV instead of some units around the picojoule.

Having a grab bag of units and domains that don't talk to each other is indeed the natural state of things. To put your foot down and say no, your industry does not get its own special snowflake unit, stop that nonsense and use the standardized unit - that takes real effort to achieve.