Lots of valid points made above.
I use my IMC almost every time I go flying. I don't subscribe to the "get you out of trouble" scenario, as we all know if you are not in regular practice it will get you into trouble.
The problem is for most renters is that flying clubs will not sign you out unless its almost CAVOK. I am always amazed when I go flying that I seem to be the only aircraft in the sky, when in fact the weather isn't that bad.
The other problems are that where I learnt to fly, having done the PPL, they didn't encourage me to go and do more and as someone has said, the IMC course doesn't tell you lots of things you really need to know.... but then that's true of the IR/ATPL too.