We still use it because it makes sense to us old farts (although I was born after decimalisation...)
Anyway, imperial measures are not
illegal, as chased through the courts by various butchers and greengrocers. I can't be arsed to dig out the citation just now, but I can if it's required. OK, you do have to charge by decimal units, ie price per kilo or litre, but you can
show price per ounce or gallon or whatever for the old farts. Just because petrol stations choose only to show decimal units is neither here nor there.
Also, most odometers that I've come across in the UK (except late - Tour, Fun - 2-smoke MZs) still show miles. Even my Skorpion, which is later than all my 2-smokes... So you end up with a weird calculation of miles per litre which doesn't mean anything to anyone! So we convert litres to gallons in preference to converting miles to kilometers. Although thinking about it, my car (Peugeot) can, if I ask it to, display distances in kilometers. I don't ask it to though...
What's a "good" fuel consumption in terms of kilometres/litre anyway?
Sorry for the rant, but that's why
I use mpg as my basis of comparison...
Anyway, with regard to the shocking fuel consumption of our first correspondent here - US miles are the same length as UK miles, yes? So talking in terms of miles per tankfull should have given him a reasonable idea about what the rest of us were getting from our bikes, in terms he could use. Hey gazorp, any news on that??