I dont understand why one would take odds on the dont pass
line. You are getting a payoff where you need to risk more money than your
getting paid, for example 1 to 2 on the 4/10. Wouldn't it make more sense to use
the odds money and just put it on the dont pass line where you are getting a
better payout of 1 to 1?
I've played and/or dealt craps for 24 years.
Considering the fact that I only play craps for fun these days, I think that qualifies me as an expert on the subject
On the pass line, the house edge is 1.41%, but
after the point has been established as, for example, a 10, the flat (or original pass line bet) now has an EV of -50% since there are 6 ways to lose (with a 7) and 3 ways to win (with a 10). Taking full odds is essential at this point to reducing the overall house edge
When you add the odds bet after a point is established, the
combination of the original bet and the odds bet effectively lowers the edge. The more money you place on the odds, the closer to an overall house edge of zero you get (you won't get all the way there, but theoretically, the house edge approaches zero as the odds bet approaches infinity).
Conversely, on the don't pass, I believe the opposite should be true.
While it makes perfect sense on the surface to say that laying odds is a zero-edge bet that the player should avail themselves of, it is worth noting that
after the point has been established, the don't pass bet now has a positive expectation for the player (i.e. you are better than 50/50 to win an even money bet after 'escaping' the 7/11 on the come out roll.
After the come out, if the point is 10, you are a 2:1 favorite to win even money (6 ways to win, 3 ways to lose).
This is significant because laying odds at this point produces the opposite effect of the limit equation that I alluded to in the pass line/odds example above. Combine the 0.00% lay odds with the (now) +50% EV don't pass bet and the more you lay, the lower your EV.