Higher peak bitrate speeds up encoding 'considerably', saves studios money

[Grubert]

Source: Dave Vaughn, quoting sources from Global Digital Media Xchange

Warner will continue to do VC-1 encodes, but they are upping the bitrate to the max for BD encodes and according to a very good source at GDMX, this will speed up the encoding process considerably because of not having to hand tweak hard to encode scenes as much. This is one of the benefits of Blu-ray with the higher peak bitrate and will allow cost savings on the encoding side.