Good points. Here's another:

3. Increase account size.

This can be an awkward thing to discuss, because a lot of traders are essentially trading on a shoestring -- which is not a criticism, just a recognition of reality. You've got the money you've got, after all. But a too-small account can seriously limit you, because you won't have that much leeway to allow for losses.

The micros have the effect of making the impact of losses, that is, risk, much less a factor, which is a good thing. So effectively speaking, it makes everyone's account larger, in a risk control sense anyway.

Bob.