The IMCR can in NO way be seen as a MINI IR.
Of course it is. It is an instrument qualification which includes instrument flying privileges for departure, cruise, arrival and approach segments.
The only restictions applying are use in Class A airways, use outside the UK and 'recommended' approach minima.
Approach minima to lower levels than those recommended for the IMC rating
require a higher instrument scan rate and corrective flying skill due to the reduced beam width of the approach aid closer to the ground. That's why, for example, inexperienced pilots in the RAF holding 'White' IRs are obliged to use higher minima than their more experienced colleagues holding 'Green' IRs.
The UK IMC rating requires proportionate levels of theoretical knowledge, medical requirements, training and testing commensurate with the rating privileges.
It is NOT, as some would try to advocate, a 'get out of trouble' rating. Whereas the daft 'EIR' would certainly be a 'get into trouble' rating.