What is the point of anerobic respiration?

Anerobic respiration is used when AEROBIC respiration can no longer take place. This is because there is a deficit in oxygen so the process of aerobic respitartion can no longer occur. The organism still requires ATP for its metabolic functions and so has to switch over to anerobic respiration. The problem is anerobic respiration produces much less ATP than aerobic respiration and also produces some dangerous toxic products such as lactic acid. However until oxygen is present again the organism must continue to use anerobic respiration in order to produce ATP.