Interesting to note that really competitive martial arts (BJJ, judo, kickboxing, etc.) seem much more receptive to weightlifting, at least in my ~30 years of experience hanging out in various MA settings. Traditional places (classical karate, tai chi, kung fu, aikido, etc.) have seemed more resistant to it.
Boxing is the odd man out, that's competitive as hell, obviously, but it seems many treat lifting like poison, although the weight class issue might account for the majority of that resistance, of course.
I'll never forget a quote from my first judo coach, he had trained with Isao Inokuma (a former all-Japan champion, and trainer of Yasuhiro Yamashita, the most successful judo competitor of all time) - Inokuma had all his athletes lift, and in fact his book shows squats, deadlifts, and presses with barbells. The quote was, simply, "There's no such thing as a weak champion."