Is getting the glutteral G right essential to learning Dutch?
Actually there are various ways to pronounce the Dutch /g/ and /ch/, depending on the region. In the south and in Flanders the pronunciation is rather soft, like the Greek g-sound. In Flanders, word-final /g/ and /ch/ are pronounced in a way close to the German /ch/ in 'ich'.
In the North the pronunciation is similar to the Spanish /j/ 'jota'.
All these pronunciation are acceptable in Standard Dutch.
True, so it is indeed not essential to learn the one specific glutteral g people find difficult, which is the one similar to the Spanish /j/. Native speakers from Flanders, Noord-Brabant and Limburg can do without it as well. :)
You're probably never going to nail the Dutch pronunciation if you do not speak it natively. The glutteral G is a sound that you do hear in Greek sometimes, but not even I can get it on the spot. You should try to say it as close to the way a native would as you can, but don't feel as though you have to absolutely bullseye it.