XLR interconnects

I read that XLR interconnects can maintain the signal over longer distances therefore it is ideal to use an XLR interconnect over rca unbalanced cables. Why then do you see cable manufacture companies produce 0.5 m, 1m, 2m, 3m interconnects for audio gear? What is difference over a 1m, 2m, 3m rca unbalanced cable? Is there any sound differences?

2007audioman