The base units of the metric system are often not very ergonomic. Why is a meter so damn big? And why is a gram so damn small? I can barely detect a gram. And a meter is frickin huge, causing people to usually divide it into hundredths of a meter, which you can hardly picture in your mind unless you already know what it looks like, especially arbitrary counts of cm. Metric's only real advantage is that it shares the same radix as our counting system.
Using metric has never been an issue in trades or sciences in metric countries.
A metre is much the same as a yard or an adult arm span. Not a problem.
Pretty much all carpentry and cabinet making is done in mm alone, the width of a fat pencil mark.
1400mm is shy of a metre and a half (1500mm), cross piece spacing might be 300mm (about a foot).
No need to have feet, inches, quarters and thirds mixing up the page, just use mm everywhere.
A gram is fine for small mass measurements, a kilogram is a good unit for heavier masses - very human scale being the same as a litre of water and more or less a litre of milk.
It really comes down to familiarity, there's nothing intrinsically difficult about metric (and much that is more intuitive than odd imperialial units and the whacky intra unit conversion factors).
As a metric user, this is an interesting point that I haven’t heard before, and I think the other responses don’t really engage with it. Yes, familiarity means this isn’t much of a daily problem – you just use divisions of the unit that are most appropriate. But the size of the base units for volume, mass and length don’t really match up well from a human day-to-day perspective.
Wouldn’t it be nicer if a litre, a gram and a cubic metre of water were equal, rather than 1 cubic metre, 1000 litres, 1,000,000 grams?
Side note that in Europe drinking products are often labelled in centilitres whereas Australians use millilitres. I wonder whether this indicates some difference in the way the two groups think about volume, or maybe it is just the fallout of some other constraint, like translations limiting the space available.
Still, the ergonomics seem to be on the side of Metric, taking into account the ease of conversion between units when all are base ten.
As a metric user: This is about your lack of familiarity.
E.g. can picture lumber expressed in cm or mm very easily. E.g., if you work with beams that are 48mm / 5 cm or 98mm / 10cm a lot then those sizes becomes second nature. Just as easy to picture as 2 inch, 4 inch, 1/2 inch, 3/4 inch etc that is in use in US.
And saying that something is 200m away is exactly as intuitive as however many feet that is. A large meter has a usecase.
I feel square metres for houses is very natural unit and square feet sounds awkward (each patch of house area is so small you can do nothing with it, a square metre gets you somewhere..).
Making yet another system of units sounds like massive pain and as someone who are used to metric I see no advantages.
As a user of both Imperial and Standard International units, I agree with you.
As a kid, one of my science educators spoke about the many benefits people gain from becoming familiar with basic units. I bought in and did so during the big metric push that happened around that time.
I ended up more familiar with Imperial units.
Then, later in life, I entered a young industry, with strong users of metric, Standard International units.
So I did the work to build familiarity just as I did long ago. Took half a year and today I enjoy the benefits.
And those are:
Ease of understanding unit values meaning in my daily life.
48x98 is exactly that dimension (i..e after planing of the lumber). Well, +/- 1 mm of tolerance/shrinkage due to drying.
It goes by the name "two four" here as well informally due to long tradition (and yes, I once did wonder why 2-by-4 is smaller than 2 by 4 inches and looked it up), but you will not see it written anywhere, in writing it is always in mm after planing.
The oral words for lumber dimensions before planing is the only context as an adult I have met inches except in US.
What we really need is a new system of units...