First, to clear what do they mean by rafts, we have three different things here:
- Slides: Slide are embedded in airplane doors (main doors), and are used to slide out of airplanes in case of emergencies.
- Slide/Rafts: They are slides as above, in addition to that they are capable of floating is case of over water emergencies (ditching). It can be separated from the aircraft once fully loaded with passengers, it is also equipped with a radio signaling device and other survival equipment. It is rectangular in shape.
- Raft: It is a separate raft, usually circular in shape and not a part of the door slides. It is loaded in overhead pins or behind last rows of airplane zones. These are loaded in aircrafts in two cases:
- When the slide/rafts embedded in doors can not carry the total number or passengers, so they load extra rafts so the total number of passengers can find a seat in a floating device in case of over water emergencies;
- The aircraft door are equipped with slides that has no rafts.
The rafts in question are the separate rafts that loaded into 737s for flights that flies more than 400 miles off shores. In these flights airplanes will not be able to make it to the land in case something happened so they must be well equipped to face over water emergencies, while in shorter flights over water airplanes can make it to the land or at least closer to the land where life jackets can do the job until rescue arrives.
Anyway, Qantas can not remove these devices, because they are required to carry these devices as per the Australian Civil Aviation Safety Authority rules order 20.11 (5.2):
5.2.1 An aircraft that is flown over water at a distance from land greater than the permitted distance must carry, as part of its emergency and lifesaving equipment, sufficient life rafts to provide a place in a life raft for each person on board the aircraft.
184.108.40.206 For the purposes of paragraph 5.2.1, the permitted distance is:
a distance equal to 120 minutes at normal cruising speed, or 400 miles, whichever is the less; or
The benefits of life rafts
Floating is not the only reason for these, people can float if they crash over water with life jackets or even seat cushions, but the freezing water can kill them in no time. So in case a plane crashed away from the land in a freezing water, by the time recue arrives people would die from hypothermia or other reasons. Life rafts have equipment to save people for longer times, including drinkable water, radio devices, a canopy to reduce heat caused by sun, flares, etc.
Anyway, from the article you linked it seems that it was just an idea by a smart person to save some money, and it will not be more than idea and life rafts will not be removed (and can not).