Rationale for BGPDNS
IP Address space depletion is not as fast and does not have the same impact as AS number space depletion and Internet core router memory consumption
With next generation IP numbering (IPv6?) address space depletion is no longer a issue
Content delivery networks like Akamai have proven that DNS RR based global load balancing is working on a large scale and does not have a negative impact on the Internet at large nor on the individual user