Now perhaps I have been lucky, I have never had a trailer tyre blow out, but then I have always checked tyre pressures before towing, and again perhaps I have been lucky, but none of my trailer tyres have ever given an indication of having a significant leak - unlike some of my car tyres.
I don't think anyone can argue against the idea of prevention being better than cure, so good management of tyres is I am certain a worthwhile investment of time.
Tyre pressure monitoring is in principle a very good idea, and if it it does alert the driver to tyre that's loosing pressure then that has to be a good thing, especially if it gives time for the driver to pull over and get things sorted before continuing their journey.
This is far more proactive approach than fitting rim bands. As far as I am concerned the jury has spoken, rim bands don't offer any real safety advantage to caravan owners. They certainly do not save the tyre, because they can only have an effect after the tyre has deflated to a very low level or lost its pressure completely, by which time the damage is done.
I don't currently a TPM system, because none of the vehicles or trailers I have had them as an option when purchased. I don't travel so far afield these days so a monitor is of less value, But when I update my car, pressure monitoring will be one item I would consider.