The difference in breathing Oxygen from a hood or the entire chamber environment is merely designated by certain codes and standards in addition to common sense and safety. A monoplace chamber is just a less expensive less complex way to deliver Oxygen to a patient in a smaller space. It makes things a little uncomfortable if you are in a small chamber already and then had to wear a hood.
Some chambers use masks but the same rationale applies.
Multiplace chambers are a way to treat a large number of patients at one time in addition to being able to offer hands on medical attention that is not available in a monoplace chamber. As far as Oxygen delivery is concerned, either chamber does the job and there is no difference to the patient. It is really a matter of preference and which chamber your closest facility has. I hope this helps. The difference in breathing Oxygen from a hood or the entire chamber environment is merely designated by certain codes and standards in addition to common sense and safety.