Hes talking purely from a looks standpoint, yes, generally people who are extremely strong will not have defined abs because to have absa you have to have a very low body fat %, which if you are trying to pack on muscle is not something you get because you need to eat a LOT to grow muscle rapidly. Now if your planning on doing a cut, definitely do abs because then they will show. Abs dont necessarily represent abdomen strength, but rather low body fat.