I agree with Shy. You use such a procedure when you're in IMC, or VMC-on-top, and you know/suspect the cloudbase is below the MVA, MSA or whatever your minimum IFR altitude is at the time. So you can't descend safely below the cloudbase in just any odd random location.
So instead you use the arrival and approach procedure of a convenient airport to safely descend below the cloudbase. Once you are below the cloudbase, you continue VFR to your destination. And if the cloudbase turns out to be too low for (safe, comfortable) VFR, you either fly the missed approach and continue IFR, or you land at the airport that offered you the instrument procedure in the first place - in effect a diversion because your destination cannot be reached VFR.
Obviously if you only break out at minimums (typically 200 feet on an ILS) it would be pretty stupid - not to mention illegal - to continue for another 20 miles under the 200' cloudbase to your destination. But if the cloudbase is at, say, 1000 feet, then this method is very convenient.