"The truth is the more corrupt registry files your computer has, the more it struggles to read them.", sorry, NOT true...
If anything is CORRUPT in the registry, you are in big trouble.
Usually Registry problems, missing file links, empty keys, and orphaned entries, are about all you'll see in the registry in terms of problem. Missing file links are the most prevalent I'd say. Point to a program or file that doesn't exist. None of these are CORRUPT in the sense the entry can't be read.
Dangerous removals are the non-obvious ones. Those 'empty' keys and missing file links, which can contain other data. Remove some (not all) of these and you can have problems, some a long time later.
Why is the Registry a contributor to slow running and booting? Because it is a LARGE file and depending how accessed it can take time. That is why cleaners tend to offer up some relief in booting and starting some programs, but it isn't really a significant time savings either. Matter of fact, many things removed, such as Most Recently Used (MRU) Lists will be put right back by programs.
If a system is running slow and gets slower over time, it usually can be traced to added start up programs and services, not the growth/bloat of the registry.