Yes.

For progressive loading I use them to keep track of how many primers I have left in the tube.

I do a lot of single stage loading and use them for every step of the process there.

I have three trays and none of them are caliber specific. They are not all created equal and I do prefer them for different calibers. At times when I am really backed up I also use plastic handgun ammo trays.

Just my opinion, but for me the simpler a universal tray is the more I like it.