No, elevated creatinine levels is only a sign of kidney disease if all else remains equal. Consuming more creatine will naturally increase production of creatinine because creatinine is a byproduct of the kidneys processing creatine.

In other words, it's not a very reliable signal for kidney disease. There is a more reliable blood test called a "Cystatin C" test.

Would you suggest that white blood cells are "not all that good for the body" because they're amped up during a bout of sickness?

Maybe they aren't! But you can't infer that from the mere correlation. Hence that phrase about its relationship to causation.