Immediate mode APIs are great, especially for debugging UIs. Unfortunately they can have some drawbacks, e.g. with things such as accessibility.
RDIC is intended to bring the power of retained mode frameworks and toolkits into the realm of immediate mode APIs.
The bread and butter of RDIC is to stabilize the call nodes. The cost of this stabilization is that the usage code must manage generational references. This makes RDIC less suitable for UIs that are quick and throwaway, for debugging, or for a prototype.
What RDIC is good for is providing a cross-frame data model that can be as rich as you need it to be.