What training/experiences make for better scuba divers

[Hydro]

a lot of training and diving books I've read talk about diving fitness, there is hardly any talk of that on this board...doesn't DIR have a whole checklist?  when it comes to freediving I admit I'm a novice and I maybe only go freediving 2-3 times a year, but I do a lot of weight training targeting specific muscles, pool training underwater, and breath holding... I think training makes me better only to a certain point, if I was actually doing what I train for I'm sure id get way better faster...

But, I'm positive physical fitness is a huge factor even if its not noteworthy. if I didn't. Weight train, I'm not sure just diving would be enough to increase strength and endurance.. id guess diving would be more likely to just wear me out.