I guess its true that you can't just equate intelligence with achievement. In my own life, I think I've increasingly used achievement where I used to use intelligence to gauge how 'smart' someone is. That comment was also trying to get at the annoyingly pervasive belief people seem to have that you must be smart because you are a mathematician, say. As an example, novices might think someone is good at basketball based on how they look on the court- but you wouldn't say someone is good unless they actually had a big positive effect on how often their team won. In general, I guess when I say smart, I mean "good" in some abstract sense.