I pin if I need to for curves or if the pieces need to line up at the corners. For straight sewing I prefer the seam guide.
I can't convince my daughter that it makes things easier though. If I'm using pins I'm usually going slow anyway so it's no big deal to stop and pull the pin if needed, but then I'm not trying to make money with my sewing either. Speed becomes much more important if you're selling your work.
The tin to the left just sounds awkward to me. I'd be spilling it constantly.
I think I know why so many machines have pin rash from putting a pin cushion on the arm of the machine. It's a convenient place for one. It might work ok if one were to make one with a hard back so the pins don't go thru to the machine. I might give it a try. I'm constantly struggling with where to keep my sewing tools (things like scissors, snips and my stilletto) while I'm sewing. There's not enough room to the right of the machine.
Sorry for the thread drift.
Rodney