True but still doesn't stop the PCs from breaking down every wall they come across.
The question is, can Geodites make tunnels? y/n. If y then no reason they can't make tunnels in-game. The important thing to note is that they create spiraling tunnels. I guess you can make a case that making tunnels might take longer than just burrowing through but not only is this difference trivial, but also highly unlikely since we're talking about stone here and not loose dirt.