It's not just that. The Boring Company wants to automate tunneling as much as possible (manual labour would be highly impractical in a spacesuit), speed it up and make it a continuous process. It also wants to power the boring machine by Tesla PowerPacks to remove the need for kilometers of cables. All of that seems suited not just for cheap tunneling but for Mars as well.
I guess mobile PowerPacks with solar panels? Just deploy a few thousand outside the tunneling area and then automate the battery switching. Could run it 24/7 without anyone ever going to Mars even.
