You're right... I lumped MMS & SMS together. I didn't realize that MMS wasn't possible through GV previously on Verizon... even if you had a dedicated GV#. My goal is to dump my Verizon Texting Plan, and use GV with unlimited free texting. However, I would like to keep my Verizon# for texting, since that's the number friends and family already use. The more I read into it though, it sounds as though this can only be achieved by porting my Verizon# to GV...Wow, thanks! I TOTALLY missed that announcement!
I'm not 100% sure I followed your question though -- as I read the post, I understood it to mean: in the past only SMS (text) messaging worked on GV for Verizon customers (using your GV number of course) but now GV users can also send MMS (esp. image) messages using GV. I think you read it a bit differently...sounds like you're interpreting it as: now you can set GV to use your cell number instead of your GV number -- but I'm not sure that's not the case.
Either way, I do a good chunk of my communicating through the Hangouts app, which is configured to use my GV number for texts and calling. Admittedly, friends who text me are a little confused..."Wait, you have ONE number that I call and ANOTHER number that I text?" but they eventually figure it out. Yeah, you might wonder: why don't I just put my cell number aside and have everyone use my GV number? It's a long story...
-Matt
These articles are old, but gave me a better understanding of the process...
Google Voice Number Porting Pros and Cons TechHive
Should I Port My Number to Google Voice