Thing is, there is a difference between "cleaners" and "registry cleaners".
The terminology is important.
To use the registry cleaner in Ccleaner you have to deliberately select the (rather poorly named, IMO) "issues" button, then the registry cleaner is available.
(From personal experience, this is a fairly reliable and tame tool. But it can make mistakes, and I have cleaned stuff I should not have using it in the past. My recommendation is before cleaning anything in the registry, you should have a pretty good idea of what it's for, how it works, and only then will you know yourself if it's safe to clean (delete) or not. Those decisions are best not left to a piece of automated software to make.)
Without having selected that button, it's another disk cleaner. A rather good one.