I have rid myself of old Restore Points and a few files in the Disk Clean Up. Now to the WHY? part. (I just keep whipping this horse

)
Info from the Windows Help and Support Center: Disk Cleanup helps free up space on your hard drive.
From that short sentence I interpret it to mean just what it says "free up space on your hard drive".
Now suppose one has space galore on their hard drive. I guess I look at that little
fuchsia and
blue circle under C..properties?? I see one tiny sliver of blue. I assume that means I have plenty of space??
I liken this to drawers, cupboards etc. in my home. I keep stuffing them with more clutter. I collect useless items and store them here, there and everywhere. But they aren't in my way.They don't bother me. I have plenty of space to gather more (plus an understanding husband). If I took the time to clean out all those drawers etc, I feel I would be wasting my time and fretting over nothing.
So given my set of circumstances, am I fretting over nothing when I go to to Disk Cleanup and try to clean everything in sight? Or is Cleaning Up the disk a task that will make my computer run better?
I love simplicity.

Thanks