I like CCleaner and highly recommend it, however, I recently saw these check boxes that were checked by default:
I really did not like the first check box, nor was I too pleased with the other two. I unchecked them since I use this program to remove junk and for privacy. I don’t trust anonymized data too much these days.
I purchased CCleaner to support the company so I don’t want my information monetized.
What you do is up to you, but I recommend doing the same if you care about privacy.