I thought I had it all figured out until you wrote: "3) You don't have to elect m-to-m to be treated as a trader".
So, I understand the difference in treatment between traders who elect m-to-m and those who do not, and I understand the difference in treatment between traders who elect m-to-m and investors, but what is the difference in treatment between traders who DO NOT elect m-to-m and investors? Or is there any difference?
Newly
P.S. By the way, I trade mostly in IRAs -- no bookkeeping required at all!