I guess it depends really. An example of being in good fitness would be being able to run for quite a long distance. Aerobic endurance would allow you to run for longer without getting out of breath but it's pretty much pointless if your legs don't have enough strength to carry on which is muscular endurance. Then again, swimming works all your body so you'd need to have good muscular endurance in the majority of muscles. It really depends what your idea of good fitness is.
But if you're doing weight lifting just to look good then yeah, it's pretty much pointless.