In answer to the initial question "are IMC/IR pilots safer?" (and I assume you mean "...safer than VMC qualified pilots?"), regardless of conditions, the answer is almost certainly "yes", as any continuation of flight training must be a 'good thing'. The caveat here is that in VMC, the IFR skills have to be used in conjunction with the VFR skills - rather than instead of them.
In IMC conditions, the answer is definitely "yes" - just so long as the pilot is current. Herein lies a problem with the attitude toward the IMCR of it being merely a "get out of trouble" rating, used to deal with unexpected poor weather, rather than something to be used actively.
I would contend that unless the holder of the rating actively uses it, the skills that have been acquired, atrophy surprisingly quickly. This can lead to an unfortunate situation where a pilot can eventually find himself in conditions for which he is 'rated', but too rusty to cope with.
I think continuing to refer to the IMCR as a "get out of trouble" card discourages IMCR pilots from practicing their skills down to suitable minimums; It's rather more than that - but I'd be the 1st to say that it is not an I/R.