How is this different from a regular EXIF viewer?
EXIF is only metadata a camera or editing software chose to write into the file. This tool also reads the file's actual binary structure directly, its true format regardless of the file extension, color mode and bit depth from the format's own header, DPI from format-specific chunks, and whether transparency is only structurally possible versus actually used by any pixel. Those facts exist whether or not EXIF data was ever written, and EXIF viewing is one section of a broader report rather than the whole tool.