The systems may be expensive, but being warned of a flat tire on your rig may prevent thousands of dollars in repairs. We took a nail in an outside dually on the rear of our Phaeton once when the tires were just 2 years old. Totally unexpected. Were able to get to a safe place and have the tire repaired and put back on. We would never have known it was going flat without the warning system and could have experienced a lot of damage.
We have a 10-tire system for our motorhome + toad and use the toad sensors while we are out driving around. When we replaced our system with an upgraded version, we put the older set on our little motorhome so we are protected no matter which rig we are driving.
Dale