While I think the metric system should be used more, I’ll also defend frantional measurements when precision matters. Decimal measurements only increase by a factor of 10. So if your precision is 1/8 of a meter, you have to either round to the nearest meter, overstate your precision (0.125 implies precision to 1mm), or essentially write a sentence (“125mm plus or minus 62.5mm”).

With fractional, the precision is built into the denominator. If your measurement of half a meter is precise to half a meter, you record it as “1/2”. If it’s precise to an pitch of a meter, you record it as “4/8”.