Not long ago Dr. Jan Linden, V.P. Of Engineering at GIPS, wrote a really good blog post called G.722 Revisited. In it he considers the trend toward the use of G.722 in the rollout of new wideband telephony projects.
Dr. Linden collected a nice stable of facts in making his points regarding the use of G.722. It’s simply old and less than optimal for use over IP networks. It’s not as bandwidth efficient as many of the new codecs, resulting is lower call quality for a given data-rate. He points to a 2007 study of ITU standard wideband codecs that is quite clear that G.722 is back-of-the-pack from a pure performance perspective.
The post is a great collection of information and he is absolutely correct in making all of his points. But I think that there may be more to it than the argument he lays out, strong though it may be.