[mlloyd]

Are they? Or do they just have superior recall? Or maybe lack test-taking anxiety? Or write or type quicker or...?

Lots of reasons a slow student can be just as smart or smarter than a fast one.

[llbbdd]

Those are all proxies for "is smarter". They have better memories, perform better under pressure, etc. Universities are meant to prepare students for the real world where these things matter.