There's a strong argument that a well-maintained car should have no sensors or instruments at all, especially not those which are not binary. If you have an oil pressure gauge, you wonder whether there's something wrong if the oil pressure drops to 87 when it's usually 90. If it's just a light that tells you if the pump is working, it's much less worrying.
It's a much bigger problem with modern cars that rely on dozens of sensors all round the car, nearly alway located in places where they are subjected to all sorts of environmental influences. I've no idea why your oil level sensor played up, I owned a Citroen Berlingo for a while that had an oil level sensor which appeared to have only a marginal idea of what the true reading actually was. A dip stick doesn't have any problem, it just tells you what the actual oil level is. Actually, come to think of it, my Berlingo might have been paying homage to its ancestors. During WW2 the Germans compelled Citroen to build trucks for them, so apparently Citroen simply manufactured them with the wrong length dipstick so they kept seizing through lack of oil.
The big risk as I see it is that all this kind of stuff lures us into a state of waiting to be alerted when something has gone wrong, rather than encouraging us to check and assure that everything is ok beforehand. In theory it's much better to spend 5 minutes checking oil levels etc on a weekly basis rather than waiting until you're blasting down the motorway.
But then who thinks "Hang on I'd better check the stabiliser is still giving out 10V" on their Saturday morning check?
