Frankly, it sounds like another opportunity for Musk to get his hands on some more government money.
The non-obvious differences are that Boring Co tunnels are smaller and unventilated, making them faster and cheaper to construct. The limitation is that this prevents combustion engine vehicles from using the tunnels. Im not aware of any other electric only car tunnels built.
On the funding side, the innovation is that the cities simply provide the permits and the casinos and Boring co pay for it. It is like constructing private above ground roads, but without the logistics challenges. It will be interesting to see how it works out.
The purpose of government is to enable people to build and do things that don't hurt others. Why should they stand in the way of this any more than someone putting in a roller coaster or casino?
The city isn't paying for it.