I agree that learning to control temps with the vents only is the best way to understand a grill. Probably 90% of my cooks are done that way.
But sometimes I get comfort in having a little insurance.
As simple as it is, a Pitmaster IQ110 has served me well for several years. It's not "connected" to anything but the grill.
I rarely use it except on overnight low & slow cooks for peace of mind..
Good luck with your decision.