AFAIK, Vallejo originally made paint for animation film studios, which is why it covers well: they don't want to be painting the same transparency three or four times

I've had more than one dry in the bottle, though. I'm also ambivalent about those eyedropper bottles — too often, changes in air pressure push paint up through the nozzle, wasting it It's also much harder than with screw-top bottles and tins to get all of the paint out, which means yet more unnecessary wastage.