There's a "trick" with the Oracle Oral mask to help some people with ear or eye problems.
First, let me say I don't recommend this mask in general. However, if you can learn to use it without the nose plugs, it has some unique advantages for nose, ear or eye problems.
Nasal or full face masks put pressure in your nose. This can go up your Eustachian tube and cause pressure in your middle ear, or go out the nasolacrimal duct and cause air to leak into your eye socket.
Properly used, an oral mask will not put any pressure into your nose, and there will be no pressure in your ears or eyes.
The trick is to seal off your soft palate, which keeps air pressure in your mouth and lungs from getting into your nose. To picture how this works, consider what happens when you blow up a balloon. Even though there is air pressure in your mouth and throat, no air comes out of your nose.
The trick is to do this same balloon maneuver when using CPAP with an oral mask. F&P says that you should start using the mask with the nose plugs and you will learn to use it without the nose plugs after a while. What I found I could do was put on the mask, start the machine, and pretend I was blowing up a balloon, feel my nose seal off, and then relax carefully and start breathing in and out. I found the CPAP pressure helped to keep the soft palate "valve" closed.
You do require a humidifier if you use the mask. I found it dried out and irritated my throat too much, even with a humidifier. I also found the sensation of not breathing through my nose was uncomfortable.
However, if you have nasolacrimal duct eye problems or ear pressure problems on CPAP, it may be worth a try. It might also eliminate some other nose related problems.