Theres no advantage to this at all.
Most mobil homes are this way.
the disavantage is the bedrooms being cut off from return air when the doors are shut.
That makes recirculation of the air impossible.
If you cut holes in the walls to let the return air pull from the room. Now you have noise in the bedroom that you can't block off. Or (noise coming from the bedroom)
A cheap way out is to cut the bottom of the doors,
Air can be pulled from the space below the door, when it's shut. Not ideal, but it's cheap.
If you try to fail, and succeed.
Which have you done ?