>>1427856>it's far harder to conceptualize large amounts of small units than it is to conceptualize fewer amounts of large unitsYou're wrong. The way that you actually remember what a distance looks like is based on what 1 in looks like, then 3 in, 6 in, 1 ft, 6 ft etc. Similarly metric users remember what 1 mm, 5 mm, 10mm, 25 mm, 100 mm, 300 mm, 1m etc all look like.
The centimetre and others that aren't powers of 10^3x are bad for general use because people are stupid and can't remember how to shift arbitrary numbers of decimal places. Using milli, base, kilo, etc. you only need to remember how to shift 3 decimal places at a time. This is why builders use only millimetres and have 0 troubles thinking about what 2400 mm looks like.
>>1427907For reasons I have just discussed, I think it is actually harmful to think in terms of the centimetre, decimetre and decametre. People who regularly use centimetres get confused about doing maths with decimals when they have to use 0.1 cm; instead they should just use mm which for general use is always an integer, and thus easier to calculate on.
And here's a big problem with imperial: Calculators are a ubiquitious tool nowaday. But any time you need to use a calculator to calculate feet and inches, you need to basically convert everything into inches by multiply the feet by 12, then divide and remainder 12 to get your feet back out. If you use mm, you just put one integer in and get another one back out, probably not even worrying if you have to round since the unit is quite small.
The role of the centimetre is important as an intuition into what a millilitre looks like. The decimetre is also like this for the litre; and the hectometre for the hectare. These are exceptions to the general rule and mostly result from the use of area and volume instead of distance.
Finally, to note: the hectopascal is actually the favoured metric unit of pressure for meteorology, at least in Australia. It gives nice 4 digit numbers.
