@beamupscotty, well...I'm bias
I think a rain sensor is a great tool to use if you already have one installed and it's just a matter of wiring it up. Think of it was an insurance policy in the event that your weather station didn't see the rain you received, provided you're in a microclimate that experiences such weather patterns.
If you're considering getting your own weather station, then it I do not think a rain sensor is needed. I'll warn you, they are pretty addicting!
Glad to hear your Iro is up and running! Enjoy