Sure, it was a "PR stunt". But I posit that it is incorrect to say that it was just a PR stunt. I believe that the symbolism involved in "Captain Kirk goes to space FOR REAL" is immensely inspirational for many people. I mean, heck, I find it inspirational enough that I know it's a "PR stunt" in a sense.
But to my way of thinking, if this "PR stunt" helps serve to get even a few more people excited about space exploration, and science/engineering in general, then that is unequivocally a Good Thing. I mean, given the number of people these days who seem quite content to abandon science/logic/reason and embrace various forms of Magical Thinking, I'm all in favor of anything that works to counter that trend.
s/enough that/enough, even though/