I love the more advanced breeding stuff, but know I wouldn't spend money on it usually so I'm happy if I get to use it just by completing a few colour quests
I see your point, but then others could also pick them up just to sell them instead of using them and that would make the whole method of not generating extra income from quest items useless.
The number in brackets are the items you got from quests and therefore you cannot sell or gift them while the items obtained from other methods are free to be sold or given away.