Avalanche airbags do exist, but cost a lot. The Rotauf MRK5 offers a cheaper and more compact alternative so that it's more widely available. What's interesting is that instead of being integrated into a backpack, the airbag can be put into other gear too such as jackets. The whole idea is to keep the MRK5 itself afloat, not the person because the purpose is to create a visual marker for rescue teams.
While there are certain limitations to the MRK5, it still helps increase the chances of being found and it's built to be affordable to all.