Well, the degree of "waste" is debatable since you get the benefit of the higher stat level during the period before it gets automatically bumped up.

I usually train my strength to one-less-than-max while I'm young then wait for my character to hit "mature" for it to get bumped to max.

Same for wisdom when I'm playing a character that isn't dependent on mana.

But if I did train strength all the way to max then I'd get the benefit of it being maxed during the ~30 hours it takes to hit "mature". It's up to you to decide whether that qualifies as a "waste" of that train. (I think it is.)