Are you fucking serious? This definitely changes things for me?
Really?
Yes in terms of bodybuilding, digestibility is everything and eggs do not digest well. They give you gas, they make you have the runs, they can have 100 on the BV but I guarantee fish, although lower, equals more protein being absorbed. Rule of thumb, if a food creates rock hard shits then you digest it well and if it gives you the runs then you did not digest it well.
Now fish is not good for everyone, some people have poor digestive enzymes for fish so it is not a good choice for them, like being lactose intolerant only we are talking about fish. Also if you have not eaten fish in a long time it might take a few days for your digestive system to get used to it but after that it is smooth sailing. When I eat nothing but talipia fish and chicken breast, my shits are hard as granite and my stomach is strong, very little gas, no pains, like I said smooth sailing.
Now as far as the biological value chart is concerned, is it important? yes but it is only half the story, your digestibility is the other half.