Right...
Like we have nothing else to do but run Wireshark or create FW rules for functionalities which ought to be "optionable" and "selectable" by the user !?
I don't do FUD, I can imagine several valid reasons for CCleaner or any product to "phone home" e.g. find out if there is an update would be the first one.
(But the functionality ought to be an setting selectable by the user - which it is, I know that I can (dis)activate the checking for updates... I don't know if it prevents CCleaner from calling home afterwards though, I haven't tested it yet.)