GW paint lids are pretty much designed to dry out the paint...
If you let paint dry out in the recesses of the pot, the pot lid closes, but not fully, allowing the paint to further dry, or even leak out.
https://www.reddit.com/r/minipainting/comments/7bpw8v/god_damn_citadel_paint_pots/Eye dropper clogs drive me nuts, and, for basecoating, I often don't need a wet palette. Besides pots, I will drip paint to the cap of craft paint. Shake the craft paint to put some paint inside the cap first.
EDIT: I *do* find it more convenient to paint directly from the pot, particularly for basecoats and because I paint to advanced tabletop. When you have 30+ miniatures to paint before the end of the week, you look for ways to save time. I actually use colored primers and washes as my first coats, but that's another story...