Between multiple copies of every Blizzard and Activision products, lots of in-game goodies, Virtual Tickets every year, and the subscription for close to 5 years, including a 2nd account for a big part of it, and already having the next year sub'd... i'd reckon i saved a mega-ton of euros. Had i farmed for it, it wouldn't be worth the time, but when you make tens of millions by selling challenge modes, mythic+ and heroic\raid mythic kills and mounts... content that you would do regardless of getting the gold, with no additional effort, i feel like it's well worth it.
Blizzard made thousands out of me, but i can't complain since i don't even remember the last time i paid anything Blizzard with real life money.