Remove and delete old revision of posts, pages and related meta content completely then optimize Database: reduce size and optimization to speed up!
It has the ability to remove completely the revision posts and pages as well as related meta tags, description and other useless things. The other plugins doesn't really remove all the waste things.
Yes, it's completely safe.
No. The revision posts is redundancy, is not the same that the normal posts. For this reason, they can be safely removed to save space and increase database speed.