Backing up every night and overwriting yesterday is how you back up corruption.

Backing up every night and overwriting yesterday is how you back up corruption.
Silent corruption, a bad migration, a slow-leaking ransomware encrypt: these don't announce themselves. They creep in, and your nightly job faithfully copies the broken state over your last good one.
By the time you notice, all 7 of your "daily" backups contain the same poison.
You need versioned retention with depth: dailies for a week, weeklies for a month, monthlies for a year. So you can reach back PAST the day it went wrong.
Rolling overwrite isn't backup, it's mirroring your mistakes. Change my mind.