In the spirit of
@Umbran reminding us that "fair" has multiple meanings, so does "great."
You had fun playing the character. For you, it was great.
For me, having to play a character like that would have been an anchor around my neck the entire game. I would feel like I was dead weight, hampering my friends, a constant liability. It would
absolutely have put a damper on my fun and would have ensured that, whether he lived or died, whether he succeeded or failed, it would have been significantly less enjoyable.
Hence, for you, he was great. For me, he would have been terrible. And it would be exactly the same if I had rolled exceptionally well and everyone else hadn't--believe it or not, I would
also feel bad playing Calahan. It's just that it would be guilt over feeling like I'm overshadowing everyone, rather than frustration because I feel like I'm being denied the chance to contribute meaningfully because ability roulette screwed me over. And yes, that exact thing (rolling stupidly well compared to everyone else)
has actually harmed my experience of a game before. My luck is almost always bimodal: either I roll amazingly well, or I roll terribly. Almost never in the middle, where you would expect most rolls to be.
But the thing is? You can do what you did with that character in a point-buy game. It's just a conscious choice. I
cannot choose to play stats other than the stats I've rolled in a game that requires rolling.
If you can do what you do either way, but I cannot do what I do in one way but can in the other, which is the reasonable choice for a game meant to support a variety of approaches to play?