According to many experts, this would be an easy way to shield humans from the radiation. A glass dome could also work but would be more expensive and could be fragile.

On the other hands, tunnels do not provide any sunlight but I don't know if humans can actually use the sunlight on Mars (so a dome might be necessary as an addition or completely irrelevant anyways).

Protection. Meteorites not burnt in the sparse atmosphere. Thermal stability. Radiation.

The article mentions that communicating Mars houses with tunnels might be the best way to deal with the loss of breathable air.