This might seem like a throwaway joke, but I think it points to something very important. The characters are missing a commonality of experience that would enable each of them to understand the other.
Without commonality, only with effort can people understand another's perspective. Here, by each assuming the other is speaking in familiar terms, the characters are unable to communicate effectively.
Using Schroeder for this strip works because he's the character with the most dissimilar perspective of the kids. He's an artist, and his focus is a higher goal. This, I would say, is at the root of his differences with Lucy. Even Snoopy is more in tune with the other kids than Schroeder.
We still get strips in which Schroeder is playing ordinary kid games, but as the strip continues we'll see him doing this less and less.
The text of ROASTED PEANUTS is copyright 2009-2011 by John Harris. No copyright is claimed over the comic strips, which are here under the principle of fair use. Strips presented for review purposes only. We love Peanuts a whole lot, and wouldn't dream of exploiting it. Please don't sue us; we're only trying to love. Thank you for reading this notice.