Well, if you want something to run without an Internet connection, iro might not be the best option for you. If you are worried about a spotty Internet connection, that's is a bit different and the device seems to handle that pretty well from my testing, your mileage may vary.
Personably if my device is not connected to the net, I don't want it to water. I'll allow my grass and bushes to take the stress for a week if I'm on vacation.
The real problem is, without an Internet connection you can construct a straw men arguments that show there is no right decision