If you already know sed/awk and you don't know JavaScript then as you say, it would make sense to just use the former tools. But for those of us for whom it's

If you already know sed/awk and you don't know JavaScript then as you say, it would make sense to just use the former tools. But for those of us for whom it's the other way round, it makes far more sense to use the scripting language we already know for the occasional text processing task than to spend time learning another language for the purpose.