I do agree with you on the insurance....
however, if you ever find yourself in the unlucky position of driving 80mph on a french motorway with a rapidly deflating tyre, you may just weight up the pros and cons! Not a nice experience!
I gradually replaced all TPMS sensors. They come with the valves which can then be bought separately (if they need replacing). The make is Schrader and have a speed rating that matches the tyres. I have had these now for quite a few years and have had no problems whatsoever. I have even had a new set of tyres since.
On the original valves, if the nut becomes loose through vibration (not difficult on our uk roads!) there is nothing holding the stem to the rim and you get sudden and quick loss of pressure.