The IMCR has safety benefits which are as a get out if jail card for the VFR pilot not as an instrument rating to be used in anger!
A common argument, but a wrong one essentially used by full IR holders to maintain their perception of their own superiority.
An IMCR / IR(R) is a rating like any other, and like any other required recency and maintained skill levels to use it safely. With that, it's perfectly useable as a mini-IR. Without that, it's not useful as a "get out of gaol card", as almost certainly unexpected flight in IMC requires a greater level of currency and skill as it's dealing with an unplanned situation, not lower. The only way to maintain that level of currency and skill is to have used the rating with planning. As the "mini-IR" you disapprove of.
It's only "Mickey Mouse" if instructors and especially examiners are not ensuring an adequate skill level. I've never heard this being seriously suggested.
Yes the full IR is a higher standard - because it is primarily used for public transport, and also a very high degree of precision is needed for flying in airways, and thus poor flying has a substantial impact upon other public transport users. That again doesn't make the IMCR "Mickey Mouse", just appropriate to flying small aeroplanes outside of airways.
G