I think SEGA released this as part of a series of game catalogues for the Mark III. Each one would feature new release games and include the current catalogue of games available.
I really love the Japanese artwork on these catalogues.
Found a nice Japanese TV Advert from back in the 80’s for the SEGA Mark III
And below is a MegaDrive Japanese TV Advert
Both have been added and can be found on the Flyers, Mags & Promotional items page.