Sandboxed applications, like Photo Anonymizator or any other application distributed through the Apple App Store, cannot be passed arbitrary numbers of individual files selected for processing in a single run. The limit is some magic number around 2500 files. Please read Sandboxing and handling many files for more details and how to circumvent this limitation.
Photo Anonymizator utilizes ExifTool to read and write metadata properties of a large number of file formats. Not all properties can be equally written, removed or redacted for some technical reasons. Photo Anonymizator provides the necessary transparency about which properties can be deleted, which can be (just) redacted and which ones can't be changed.
So far there are no other known, major limitations. But we'll see as Photo Anonymizator experiences broader usage.
