Are sectional paths correct across "long" distances?

vincent p. norris writes:

Any straight line through the exact center of a chart, regardless of
direction, will be precisely a Great Circle. A line across a corner
of the chart will be the poorest representation of a Great Circle, but
still "good enough for government work." Probably as close as the
average GA pilot can hold a course, anyway.

I decided to finally test this. I drew Great Circle segments on top of
the straight line path. The difference is small but significant.
https://aviationtoolbox.org/Members/...=1453666.76955
(The yellow line is straight. The red is made of ten GC segments.)

Time to start using GC calculations...

--kyler