This sits as an umbrella over many of the other granular OCR requests - the ability to trigger Apex and Workflows from OCRs, the ability to customize the OCR as if it were any other Salesforce standard Object, and a number of other use cases that have been requested individually over time.
This is also critical to nonprofits using the Nonprofit Starter Pack: While Salesforce.com offers Person Accounts for understanding individual behavior in a B2B context, the Nonprofit Starter Pack has historically opted for an Account/Contact model of some nature (Individual “bucket,” One-to-One, and Household Account). The problem is that assigning donation credits to people as an individual is relegated to the Opportunity Contact Role Object.
The Nonprofit Starter Pack is core to how many, if not the majority, of nonprofits implement Salesforce, and has existed in some form since the 2008 era. Using OCRs for donation accreditation is itself a customization of the base Salesforce platform, however, the decision to do so was made in an era when the base platform wasn’t nearly as extensible as it is in 2015. OCRs have become the de facto standard for donation handling for nonprofits, and require special consideration of their needs in platform review decisions that make it into the Seasonal Releases. If not just for the myriad of related for-profit requests, but for the explicit needs of nonprofits.