Uhh...not true. A powerlifter benches with the grip that allows them to lift the heaviest weight. There are shirts designed for an elbows-out wide grip, and then others for an elbows-tucked closer grip.
Do what works/is comfortable for you, and then ask someone who is in the know to check your form. If it's not potentially dangerous, then do it. No specific grip is going to give you better athletic performance, increasing your power will do that.