I'd assume that it's still semi usable. Just like Wii Browser and DS browsers are still semi useable. Probably not a lot of places you can still go, but given a connection and some net know-how you should be able to get it online.
Subjective? No, most all of these are worth about 5 bucks a pop if they have their original cases. Nothing subjective at all about it. It's not less common than any of the others. These were given away with systems and accessories for most of the life of the system (wooo 18 months). There are other versions with demos on them. 2.5 has Swirl and some other stuff as well.