It doesn’t!

The first life on earth was anaerobic- it metabolized without oxygen. The evolution of oxygen producing life (photosynthesis) was disastrous for these early life forms and almost all of them were wiped out by the emergence of an oxygen rich atmosphere that was highly toxic to them.

We still have some life that can survive via anaerobic metabolism - for example Botulism can metabolize aerobically when there is oxygen available or anaerobically when there isn’t. For us the second path is terrible because it produces highly deadly (to us) chemicals in poorly preserved food.

Another, very well known, life form that uses anaerobic respiration area yeasts. In oxygen free environments they anaerobically metabolize sugars into alcohol and carbon dioxide. This is how we make all alcoholic beverages, and get bubbles in them!

Humans can, for a very limited time, metabolize anaerobically - typically for very short bursts of time when oxygen transport systems are unable to keep up with as very high intensity demand, like a 200 yard sprint. The byproducts of this are harmful to us though so our bodies will fairly promptly slam on the brakes and cause your muscles to seize up and force you to stop.

Anyway - why is oxygen such a preferred metabolic option? It enables a much more efficient production of energy than anaerobic options that we are aware of, and can output much higher energy - so lifeforms that we’re able to adapt and use it were able to do outperform any that weren’t.