One thing I have learned above all others from BJA, it that EV alone is not the most important factor in evaluating a game or method of play. Rather, it is the relationship between risk and EV, in this case stated as DI.

Since DI increases as standard deviation decreases, it seems to me that any method of play with a positive EV and a standard deviation of 0 would be a very good game!

If this is true (big if!), why is Insuring a natural not the preferred play? Insuring a natural has a positive EV with a standard deviation of zero. My simulator is too simple to calculate the standard deviations, but I'm sure never Insuring (as in BS) or Insuring according to the count must have a standard deviation of greater than zero.

So it seems to me the DI for Insuring a natural must be much greater than the alternatives.

What have I missed?

Thank you!