What's the sense of observing yom kippur and pretending to repent if the sinner goes and sins again?

but god doesn't expect us to never sin again that is why he commanded us to observe yom kippur every year. god knows and we know, we're only human, we'll sin again. on yom kippur we ask god to forgive us for our sins, we don't say we'll never sin again becuase that is impossible. that is how god created us, with flaws and faults.