Here in Scotland when buying timber the conversation include conversion: “Four 150 by 50 (mm) please”- “Is that 3.5 or 4.8 (m) lengths of four by two?”. Sheets of OSB/ply etc, can be 8 x 4 (feet) or 2.4 x 1.2 (metres) and there is a slight difference which builds up when laying sheets side by side.
Cooking is not an exact science so measurements and quantities in SI units can seem a bit of an overkill in the precision department. However, having been brought up with SI units, and weigh and measure ingredients in SI units, it is a bit jarring to come across a web site which has a recipe in a mish mash of systems and abbreviations, especially a) the elusive tbspn (half, whole or heaped), b) fluid oz (is that a mass or a volume?) and, c) the cup (where the cup size it not specified and when I ask my wife what size cups she has, the answer “A” does not help).