no he's really looking for diamond, gold is just something he happens to find while digging
Honestly, diamonds aren't actually that helpful long-term, while gold can be. In vanilla, you mostly just need enough to sustain your diamond tools/armour. Meanwhile, if you're going to do any significant amount of rail work, you're going to need lots of gold for powered tracks.
Playing modded, both gold and diamond are really needed for high end equipment.
Lets use the Wyvern Chestplate for example You need (going from base material) x13 diamond x20 gold x1 netherstar x36 redstone x34 Draconium
And Draconium, without going to the end. Is the hardest thing to find in most modded versions. If you want the full set x13 diamonds chest)+ 10 (helm) + 12 (legs) + 9 (boots) x80 gold x4 netherstars x16 redstone blocks x136 Draconium
This is just for an armor set that isn't even the best one
If you're playing modded, though, materials are significantly more plentiful. 44 diamonds and 80 gold aren't even that much by vanilla standards. As you said, the Draconium is by far the more limiting resource.
That is true
If you can make a huge gold ore barry farm, and have the calculator mod, with those two you have unlimited of both. 4 gold bars = 1 diamond 9 gold ore barries = 1 gold bar.
Plus i found a good way to farm them without mobs appearing. Not sure why i didnt think of it sooner. Just use slabs in a dark hallway, and have the berrys growing on both sides ---