Eighth of an inch is about the limit of precision in most circumstances.
Countries that use Imperial for day to day use still do tend to use metric for a lot of purposes including many engineering tasks. (Imperial is terrible for certain types of engineering calculations--especially involving pounds and lets not get into slugs--but it's fine for cooking even if I tend to use grams for weight on my scale when baking.)
"Imperial countries" are actually pretty hybrid for the most part to greater or lesser degrees. UK is more SI than the US but they still commonly use a lot of Imperial units including some "odd" stuff like stones.
I presume if you think eighths of an inch is good enough then you mostly work with large objects. Luckily outside of USA, Liberia, and Myanmar inch-based scales are rare nowadays, but I still come across specifications in small fractions of inches for such things as manufacturing tolerances, drill bits, coating thickness, cable diameters.
Informal measurement of humans and beer is a nice quirk of the UK system, but in my experience it's not commonplace to use imperial units for anything where accuracy is important (except maybe jewellers, and arguably road speeds/distances).
Countries that use Imperial for day to day use still do tend to use metric for a lot of purposes including many engineering tasks. (Imperial is terrible for certain types of engineering calculations--especially involving pounds and lets not get into slugs--but it's fine for cooking even if I tend to use grams for weight on my scale when baking.)
"Imperial countries" are actually pretty hybrid for the most part to greater or lesser degrees. UK is more SI than the US but they still commonly use a lot of Imperial units including some "odd" stuff like stones.