The problem with a non-Luer Lock syringe is that you're using the same needle to draw and pin. You dull the needle by piercing the rubber stopper on a vial. Plus, as you said, you're restricted to short needles (fine for triceps/delts/etc) but it's also a 1mL syringe. Most dosages are 1mL or more. Doesn't sound like a very good option. You're better off pulling air into the syringe to clear the needle and then swapping to prevent waste.
Dulling is not a problem with these pins as they are 25G. Yes, it can take a little time to fill with the heavier oils but they work fine. I have pierced an old vial, then a new vial, and finally my skin and still without any problems with dulling. Never been a problem. I don't throw the needle like a dart, rather I place it against the skin and just push it in. This has always worked better for me. I inject in the hip area more towards the front and the shorter needle is just fine at that location. Been doing this for years. As I said, the volume can be a problem for many so you do have a point.