5 feet is almost precisely 1,5 meters, a conversion very easy to do on the fly. Divide for 10 and multiply by 3. For instance 30 feet is 9 meters.
The problem I think I have is not really about game balance, so I take that back.
The point is: measure conversions usually bring some issues that most of the time are dealed with rounding some numbers and I like too see the original to decide by myself if the approximation is worth or not in the circumstance.
I'm not thinking only about feets and meters, but all measures that are used in the game and sometimes don't translate easily. There are rules like encumbrance and jump that rely on certain unities of measurement that when converted end with weird fractured numbers.
For instance, if you use encumbrance rules you rely on the weight of the itens that are usually given a round number in pounds or a simple fraction like 1/2. If you want to make it easy for someone who are thinking in the
ISU you end with numbers like 453,592 grams for 1 pound. You could round to 500 or half Kilogram, and decide that's good enough, but I'm not sure.
There is also the miles, which convert to approximately 1,6 km, gallons aprox. 3.7 liters, etc...
Perhaps I'm thinking about this because I had some issues with some conversions from Mutants & Masterminds 2e, but that game tend to deal with very big numbers where precision issues can make a diference. Anyway, it might be just a personal taste and perhaps I'm crazy, but I like to look at the numbers "as intended". I'd even manage to do a rationalization that if you're portraying a medieval world, it doesn't make sense to talk in very "scientific" measure unities, but that's just crazy, I know.
So sorry, if my previous comment sounded harsh, but I still prefer conversions as an extra. By the way, Onyx Path did a good job on the V20 book where they kept the Imperial Measures, but offered a approximate ISU conversions side by side.
PS. I having a problem with the reply feature. When I try to compose my comment in the box it doesn't accept empty spaces. That's why I'm not properly quoting comments.