I understand the point that was being attempted, but the problem is with the illustration. The two lines should be equal lengths with one being divided into 8 parts, the other into 6.
But 8/8 is not equal to 6/6 in the illustration.
The first thing that I saw wrong with this technique is that using a number line to figure out which fraction is greater requires the fifth grader to draw a perfectly spaced and scaled set of lines on which to do the comparison.
They demonstrate that weakness with this problem by not making 1 meter equal 1 meter.
Finally, they use "further" rather than the correct "farther."