I think the specials served the purpose of trying to get Disney Tweenybopper fans exposure to the Muppets. It's basically an experiment that was mildly successful if anything... though it basically just got kids who watched those shows to say "YAY! More of the same with stuff we can ignore." Some of them braindead tweenyboppers complaining that a puppet is hitting on some celebrity they'd never EVER get a chance with.
If these are released on DVD, the more the merrier, I suppose, but this was a phase of Disney I think we should just let completely pass. The whole 2004-2007 tween focus... they've thankfully came a LONG way and gave us some much better stuff since. And again, I'm sure we'd MUCH rather Seasons 4 and 5, Muppets Tonight, the TV specials, and all that long before these shows.