There is no match between a greater dragon and a whyte wyrm, even if the wyrm is fully trained and the best of possible wyrms you can have and the gd the cheapest freshly tamed one you can find.
Well, in fact there is no match between the greater dragon and anything else you can tame, for some reason they didn't boost the wyrm too (a frost wyrm with gd stats would have been so cute).
Bane dragons are collector's stuff, they spawned during some old event, then they used to be in the new Abyss dungeon for a while until the devs removed them again. They have a somewhat decent resistance set so they might be not completely useless but nothing you can think of taking with you for heavy pvm fights.
Here in Europa shard pricing varies a lot, once i saw a very good firebreathing bunny sold for 500k and sometimes in new Magincia i see for 1 million creatures i would barely donate to the zoo.
Note that if you have high skill (well, 120 really) and you use honor taming, getting a greater dragon is a piece of cake: you just have to stay near it and spam animal taming. It may take a while to find a "keeper", the range of possible stat/skill/resistance combinations is pretty wide.