I really like the message of this song, that just because you have a best friend (and/or roommate) doesn't mean you have to spend ALL your time with that person. As someone who encountered a lot of co-dependent behavior from peers as a kid, I can say that is a very valuable lesson to be taught early. Also, because I remember the days when almost everybody on Sesame Street thought that Snuffy was a figment of Big Bird's imagination, I can never get enough of seeing Snuffy interacting with other characters.
"Hi, Snuffy. You look kind of sad." To be fair, that's kind of Snuffy's baseline.
The only thing I don't like about this song is that sometimes when Snuffy says "Bird" it sounds like he's saying "Bert". But the context makes things pretty clear.
Ernie suggests to Snuffy: "We can play in my room." Umm...that would probably be easier said than done.
One interesting thing about this sketch from a technical standpoint: usually Ernie has live hands, but in this sketch, his hands are operated by rods, the same way that Bert's hands are.