Cycle Of Life And Death

Why is samsara(cycle of life) so important to Buddhists?

Why is samsara(cycle of life) so important to Buddhists?
Basiccally why is the cycle of life and death so important to Buddhists and Hindus.

Through the cycle of life, death and rebirth one gradually moves closer and closer to a life where they can attain Nirvana or Moksha, escape this world and be free from suffering or return to Brahman. These are the respective goals of Buddhism and Hinduism.