I can understand why it doesn't seem to make sense while leveling, but at endgame, you really only collect from 1 important node at a time, draining almost all of your GP in the process. Then you return to a town or teleport off to wherever the next node is (ie. Coerthas Western Highlands -> Azys Lla -> Dravanian Hinterlands). If you could easily recover all of your GP between those nodes without any items that would be nice, but the items would be mostly useless and they'd probably drop the number of scrips any of those things are worth/ up the number of materials required for recipes to compensate.

I really just dislike that GP doesn't seem to regenerate while you're in an instance (I think) or logged out. Otherwise 400 when you switch to the class is fine. If you're at all serious about gathering you definitely have at least a few dozen cordials on you all the time.