BCAAs are not a substitute for protein in your diet. I certainly wouldn't be relying on protein from BCAAs as it's an incomplete protein. It only contains 3 amino acids. Compare to egg whites which are a com plete protein and contain Histidine, Leucine, Methionine, Threonine, Lysine, Isoleucine, Phenylalanine, Tryptophan, Valine, Alanine, Aspartic acid, Glutamic acid, Proline, Tyrosine, Arginine, Cystine, Glycine, Serine.
The main benefit of BCAAs is it's high Leucine and isoleucine content during times of acute physical stress.