"If I have a friend who squanders their money while I save and build up wealth, are they stupid?"

No, they are probably "helpless". If they actually have a more fulfilling life then they may be "intelligent".

The distinguishing feature of "stupid" people in this typology is that they are the ones who cause grief to others with no gain to themselves. This is not the same as being unintelligent; the intro to the article points out that nobel laureates are just as likely to be stupid as anyone else.