At this point in time the CCleaner staff are not engaging with this forum.
It may be a while before you get ‘Official’ answers.
My Guess is simply that they wanted to add a Piriform folder so that it can contain other Piriform products and not just CCleaner.
Have you tried using the v7 installer offline?
(I have a list of things to test with v7 but haven’t had time to get round to it yet).