Those badges are lovely and a great idea as a convention freebie. I used to have a badge-making kit when I was a youngster. Wish I knew what happened to it
Picked up a button maker quite awhile ago; can be fiddly finding an image that fits, size-wise. However, I've played with many ideas.
Sir Randall played a version of Blue Max, and suggested I make national buttons for players. I did the same for the Tuffley-verse major powers for Full Thrust.
I've taken old White Dwarfs for Warhammer images. These made good giveaways; too bad most of the current images are blurry b/w or photos of figs. Not good for badges...
Medal images can be used for simple, small winner trophies in tournaments.
I've even seen them used as con id badges.
Alas, most of my projects were started but petered out before fruition, but I've still got the maker and blanks, and will give it a go again.
Doug