Purpose of a Canon EF 50mm f/1.4 USM?

Looking for a gift idea.

The recepiant already has the bundled lens, which was a Canon 24-105mm f/4 IS USM.

He takes a lot of low light photos. My main concern is overlapping. I don't want to get him the 50mm if the 24-105mm can do everything, even if its just SLIGHTLY worse, than the 50mm. That would defeat the purpose of getting another lens.

Are their any substantial benefits that the 50mm has over the 24-105mm? And more importantly, which of the two will show noticeable quality in terms of low light photography?