I think it is worth it.
If nothing else once you have it you can use it during your hour building. Go find some benign IMC and practice your scan. Go shoot a few approaches or sit and perfect a decent hold over some beacon or other.
Your IMC instructor will be able to give you some excellent sortie profiles for you to go and practice. This will help enormously once you come to your IR training.
I was teaching people in Jerez for their IR at an hourly rate of about £60. Just prior I could have taught a lot of the basic stuff for £10 at a small school...
The IMC is an excellent safety aid as BEagle pointed out. You are in far more peril scud running and running out of ideas than you are climbing to MSA and getting yourself a radar service.
One hears all manner of stories about people who used their IMC and IF hours to knock down the costs of their IR and CPL. I am unsure of the current position with CAA FCL. Its worth a good long look though.
With sound judgement the IMC rating can directly contribute to a min hours IR first time pass. Something you should all aspire to.
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