I have this slides which helped me a lot about Co-Termination and PDL.
For me the advantages on PDL are good for Service Providers, because it allows them to move licenses from and to different organizations with also the support of individual device shutdown.
Also good to know is, that it is only a one way conversion.
Did not hear about phase out one of the licensing models and I think it is a good thing to have both options.
hope that helps