A good protein powder has BCAA's so they aren't essential.
HOWEVER...
If you use enough (up to 20 grams a day) they really can make a difference. BCAA's are a very overlooked supplement. They are expensive though. If you're going to use them, make the investment to use enough, or don't bother.
It's kinda like Primo. If you can only afford 100 mgs a week, it's a waste. You'll get nothing out of it. But at 500 mgs a week...wow.