Go big or go home
As I build this new garden, I'm faced with some garden bed edgings from previous gardeners. Now, I know that all gardeners have their own thing and the right to enjoy the garden the way they want but...
Go big or go home.
I can't figure out why anybody would use small baseball sized rocks to edge a garden other than the fact that they've dug them out of the garden and they're free. They don't stop the grass from encroaching, you can't mow over top of them (means you have to pick out the weeds and grass by hand - a lot of work) and only serve as a minor speedbump for marauding problems such as slugs.
If you want to use rocks - use big ones. Pick 'em so you can hardly lift them. That's a rock. That's an edging. The rest are simply my current pain as I have to pick them all up and toss them into the fill pile.
Use edging that's in scale and size for your garden. In my case, I'm creating an English cottage garden and the tiny flat rocks belong at some seaside resort for small children. I'm going to be using wood - something that fits into the rural setting of my garden. I'll save the rocks for the waterfront designs and maybe the bigger ones for creating a sitting / deck area.
But little stuff has to go.