Most UNIX derived operating systems have a method of scheduling scripts to run periodically. BSDs like macOS run daily, weekly, and monthly maintenance scripts, and traditionally these would fire late at night.
It was never actually important to worry about making sure these ran every day on macOS. As far as I can recall, on an out of the box OS X install there was never much more than log rotation (archive the day's system logfile, delete old logfiles). Log rotation isn't actually an urgent task which has to get done, and besides, very early on, Apple made sure maintenance scripts would run on boot if they hadn't had a chance to run while power was off.
This didn't stop nervous people with poor understanding of what this maintenance was for from getting paranoid about forcing it to run at least once a day, so utilities that forced it were mildly popular. Like most such things these utilities provided nothing but placebo effect, but because placebo effect often convinces people something real is happening, you'll get those who swear by it.
These days it's even more pointless. The traditional daily/weekly/monthly UNIX maintenance scripts are now regarded as legacy by Apple, so out of the box they're just a placeholder that does nothing. They exist only to satisfy the dependencies that some traditional UNIX software has. If you don't have homebrew or MacPorts installed (these are utilities for installing such software), you almost certainly do not need to worry about the maintenance scripts. Even if you are one of the tiny number of Mac users who uses these systems (like me!), you almost certainly don't need to worry, because once again Apple does make sure to fire these scripts on boot if one of the normal trigger times was missed while power was off.
