Yeah, I gotta echo this. Even before I started cashing in on all the Smugger's Caches all over Skellige, I had more than enough to purchase everything I needed, and then some. Probably would've had a lot more had I realized sooner that I didn't have to purchase all the different variety of Crossbow Bolts, since the ones you can pick up from Bandits and treasures/caches are more powerful.
I never bought any weapons or armor, save the ones that came with the Expansion Pass. Only crafted the Witcher gear, picked up everything else from Points of Interest.
I did end up using the White Orchard money glitch in the end, because funding the rune guy took almost everything I had, and I wanted enough for the house in Blood & Wine. But, again, probably would've had much more if not for the Crossbow Bolts, and I probably could've easily saved up that amount in Toussaint.