It's 2018. Not sure if it's really necessary to use something like CCleaner on Windows 10. The built in disk cleanup and defrag tools have been perfectly sufficient.
Perhaps the negative response will encourage the developers to add a working option to disable the telemetry. For now, the previous version without data collection (v5.44) is still available on the file hosting site FileHippo. [1]
More of a privacy thing than a space-saving thing, really.
Yes, Windows (7, 8, 10) have some curious folders that tend to fill up with something, like winsxs and Installers, but you can't just delete stuff there anyway, it is needed by OS, so malware like CCleaner won't help there.