> which are two foot or 60cm across

That's not exact though. 1ft = 30.48cm. If you are working in your own garden that's probably close enough, but for anything else the errors will quickly add up. Tiles are often made to have sides that are 30cm or 60cm, if you try and tile a bathroom that is 12ft across assuming tiles are 1ft each, you'll get to the other side and end up with an odd piece.

I was born and raised in the UK, and honestly I think we have it worse than the US. At least the US consistently uses the same units (although the wet vs dry weights are confusing). When I learnt to drive I suddendly had to learn what feet mean, even though I'd never used them before in my life.