Probably not in BMX, no. In that era of road cycling, before the advent of carbon fiber componentry, it was arguably worth it. Since things like derailleurs and brake levers aren't load-bearing, the strength of them doesn't really matter, and those few grams can make a difference when you're going up the side of a mountain.
Even in road cycling it's no longer a popular method of weight reduction, though, since carbon fiber tends to crack and/or break when you put holes in it.