SIFT is free to use for research purposes. Tons of people, papers and algorithms in computer vision use SIFT. It's a very neat detector and the de-facto standard which is no doubt why it's in there.
It is good to provide for research purposes - however, why not provide SURF as well if this (research comparison) is the case? SURF is equally popular and arguably more effective. Way more popular than "Tonality" and the other features at the tail end of the list... have my hater hat on here for a moment.
