If the plumbing loops down, the hot water won't circulate and you won't need those heat trap nipples.

Please elaborate on how the water circulates.

On our water heater, cold line comes in and hot line goes out and the lines are not connected together. In order for cold line to have water flow, the hot line needs to flow. When out flow is 0, in flow is 0 and there is not fluid flow so no circulation. In order for the water to circulate, water would have to flow out the hot line and back in on the cold line which would mean that you have a defective water fixture somewhere that is letting hot water mix with cold water when the faucet is off.