How you use the IMC depends on how current you are, and staying current is the biggest problem for IMC holders.
It can be hard for those who rent, but staying current is hard if you are a renter, anyway.
I don't think either being an IMCr holder (rather than IR holder) or being a renter rather than owner makes it particularly harder to stay current.
The privilege limitations of the IMCr do not meaningfully reduce your ability to stay current. The only exception I can think of is that you can't do approaches into the Channel Islands airports (and France, of course).
Similarly, from the time I was an IMCr renter, if anything, it was easier to stay current, because those days which were ideal for you to practice in real IMC were also the ones that the aircraft were most available.
The real barriers are time, money and inclination. There is no escaping the cost of the flying, paying for approaches as applicable, and paying for an instructor from time to time. There is the extra brush-up reading and the charts and planning. You can't stay IFR current on the money and time budget that you could be reasonably VFR current. But having said all that, there is nothing to stop an IMCr renter staying current. I don't rent, and I fly with an IR - but in reality I find I have to do special currency trips on a days with bad weather, or with a safety pilot, because you just don't encounter real IMC that often in the course of normal to keep good currency in all phases of flight.
Renting a school airplane for which you don't pay approach fees at the home basecan be excellent value. The fees saved can be a very significant part of the rental cost.