And stamina is stamina, completing a triathlon gives you another thing to point too when arguing his work ethic.
Do not agree with the bolded part. Do agree with the other part though. Stamina isn't stamina. There are different types. A marathon runner would gas within minutes of being in a MMA cage. I'm not saying doing triathlons doesn't help at all with cardio but if the Diaz brothers conditioning program consisted primarily of trithlons they would gas quite easily and quickly.
This isn't something I've just come up with . I buy Fighters Only magazine every month and there was an article in the training session about conditioning. The dude said that the only thing long distance running is good for is long distance running.