This is a pretty cool character that the company took a chance on. The TOS lineup had gotten kind of random by the time the Mugato came out, but along with the Gorn is one of those rare characters that grew in popularity decades after the original episode aired. There were a few characters like that throughout TOS, and I think this one did remarkably well as a figure just due to how wild it is.
Despite having more than 200 figures back in the day, I never did get around to buying one when they just came out -- I was heavily favoring TNG, DS9, and VOY figures at the time.