Free online converters sometimes limit the resolution of the LUT (e.g., converting a 64-point LUT down to a 32-point LUT), which can slightly degrade color accuracy in extreme grades.
If you are a multimedia creator shooting both video and photo for a brand, converting your project's video LUT into an XMP profile ensures your Instagram photos match your YouTube videos perfectly.
A Cube to XMP converter does not simply rename the file extension; doing that will corrupt the file.