Absolutely agree with FFs statement on the legal (and practical) position of the IMC rating. It is not a "get out of trouble rating" for the simple reason that instrument flight skills fade very rapidly with lack of practice. If you need it, then you have to be in practice and that means using the rating. ie flying in IMC.
This "the IMC rating is not for using in IMC" business seems to have started about four years ago with the publication of the CAA General Aviation Safety Sense Leaflet No 23. These safety sense leaflets are generally very good, but I believe they were written by one person and in this particular one I believe he got this particular point wrong. I think this is a pity because there is a lot of very sensible advise in the rest of the leaflet.
I could expand on this considerably, but briefly, having the rating ensures legality but it is being proficient and in current practice that maximises safety.