Yes, PrivaZer is safe to use on RAM, HDD, and SSD. It uses secure deletion methods that don't harm the lifespan of your devices. However, like any tool, excessive use can cause wear, so use it judiciously.
PrivaZer Developers changed the default disk cleanup method in the latest release from "Secure Deletion" to "Normal Deletion + TRIM" which is a better option for SSD lifespan.