What I did back when I painted miniatures was that I had a small box with the colors, and lent it to my friends, on the condition they added one color for every miniature they painted with it. Total win-win. It cost them 2.50 per figure, and the range of colors ever increased. In the end, there were over 30 pots in the box.

Sounds more like a YSK than an unpopular opinion.

I think the only thing I would add is that if you are doing a large number of minis wearing uniforms (looking at you Warhammer folk), then I would mix my paint in large batches. Getting it exactly the same again might be a pain.

Most the time the defense I hear for this is that the pigment particles are smaller in the mini paint brands. Not sure on the validity to that. I just use normal acrylics with a bit of water if they are too thick. Though I will get washes like Nuln Oil from the premium brands.

They do have to be good quality paints as some of the cheap ones are a bit gloopy, but otherwise very true.

Do I look like I wouldn't end up with a brown sludge if I tried mixing them myselve?

Also, I'd like to have a uniform paintjob over an army and not end up with a bunch of slightly off coloured minis.

Aren't the craft paints only matte, and begin to chip after a while?