Yeah I've actually built a system like this before. The nodes didn't have power supplies with strong storage capacity but did have an infinite source of limited

Yeah I've actually built a system like this before. The nodes didn't have power supplies with strong storage capacity but did have an infinite source of limited energy harvesting (they could extract a tiny amount of power from the environment they were monitoring). With the walkie-textie type system you're making a different tradeoff here though that would have to be measured and assessed. Now you've got a couple of knobs to twiddle with: - What's the max acceptable latency between sending a message and receiving it? That determines your beacon interval and becomes the factor that determines your battery life (effectively your Rx duty cycle + Tx beacon energy). - Does transmitting the beacon at your beacon interval and only having the receiver run in a limited window around that beacon result in a larger or smaller net power consumption? That's going to depend significantly on your transmit power vs. receiver power.