The player can fit through 4 wedges like this vertically:
They can’t fit through the same gap horizontally though you’r right.
The other problem of making it easier to think about is perhaps a better argument. If I have the following set of blocks:
And I click what should happen? At the moment (without the ability to dig into walls) you get this:
If you could dig walls we end up with this:
Which I think is wrong. Most people would want the first result.