Yeah but trading them means you need to find someone to trade, and there are exceptionally less Masker and Sera users than Drakon users.
Either way, I always go for the biggest mineral (including blue and green), but that's probably because I already know I have enough minerals to get up to 3 of each Sprite up to Level 105.
So I don't care what I pick up.
Also, people don't seem to understand that minerals are still shared (at least they were when I last checked, which was recently...), so does it really matter what they pick up as long as you yourself get the biggest one?
Trading minerals would definitely be interesting. It could fill in that gap of people wanting to sell the minerals just like the old days.
However if more sprites are being implemented, I feel like this would be the best time to do this. We can already trade food, so in the we're just trading dust to each other right now.