It isnt really bad, but isnt necassary like a fresh water tank.
Th bubbles can stress fish and corals, and alos raise the PH in your tank.
Not to mention all the salt creep you will get forming on the outside of the tank.
Like said above, for salt water all you need is good water movement to create oxygen.
Bubbles wont hurt anything depending on how many you have, but a simple bubble wall or airstone wont have any negative affects on the tank. The only pain is the extra work you will have to do to keep it clean.