The advice to know map/compass first then GPS is wise and I preach it myself. However there is another truth lurking out there: a lot of map/compass guys don't know how to really leverage a GPS.
You may say that map/compass has served you fine for all these years and you don't need to know how to run a GPS like a scalded ape. But then, musket owners would feel the same way about an M4.
"I've done quite well with my slide rule, why should I care about silicon chips?".
There's deficits on both sides of the argument.