Are hexes just traditional for hexcrawls or do they allow for fast and accurate measurements of distances? Take a look at following image.
This is a real world map with a winding path to the observation tower. It as a small scale so we are forced to use an odd measurement for a hex. One-eighth of a mile or 660 feet per hex. When I drew this over top of the image it each hex measured from top to bottom 0.365 inches. The purple path I drew over the original map path measured 6.027 inches. Making the true length of the path, if you hiked it, 10,899 feet or 2.06 miles.
At a game table you could have a device with a wheel that you could roll along to measure the true length of anything on the map. But that not a common piece of equipment a person is likely to possess.
The virtue of a hex grid is that from each hex there are circles of hexes surrounding it out to an arbitrary distance. This makes it very useful to measure distance quickly from a center hex to an arbitrary point.
So what if you have a hex filled with winding paths inside the hexes. Well if I counted up the hexes that the path touches it comes out to 13 hexes or 1.625 miles. (the red numbers) Not very close to its true distance. However if I double counted (or even triple count) hexes (the blue numbers) with particularly convoluted paths. Then I get about 17 hexes or 2.125 much closer to the true distance of 2.064 miles.
Like any tool you need to use your best judgement in using this. In this case you need to estimate by sight whenever a convoluted path inside of a hex means you double or triple count it.