These Mac cleaning tools also include useful utilities such as memory cleaning and a duplicate finder, as well as allowing you to control your privacy.
A cache is like trashcan, if no one takes it out, it will keep on building up until it becomes too much for the home (or, in this case, the system) to tolerate.
The result should be a much cleaner, better performing Mac computer, since these commands remove the system, user, third party and Apple-made app cache files from your Mac to reclaim the disk space occupied by these temporary files.
When you start using Mac optimization software, essentially you're allowing a knowledgeable developer to access your computer and run maintenance scripts and low-level commands on it.