If you added a dome to a mars base, greenhouses too, and added 1/10th Earth pressure (10 kPa) you would be able to grow lichen which could be a food source and a source of oxygen from the carbon dioxide in the air. In addition you could reduce the need for radiators for cooling the habitats, since it is likely they will have to expel heat similar to the ISS, the higher pressure would increase convection and increase the temperature within the dome. Lastly you would reduce the pressure difference of Mars's atmosphere of 0.6 kPa and the dome air pressure of 10 kPa and the habitats pressure of 50 kPa which would reduce structural issues. (Greenhouses might be set in between 10 and 50 kPa.)
Edit: I've removed the part about not needing a pressure suit within the domes, which I see now you'll need at least 33 kPa.