Maintenance: Assembly/disassembly is much, much easier

Adjusting: Its much easier to adjust, usually a single allen key will do it. The feel is different but the procedure is easier.

Handlebar height: If the steerer is long enough you can move above/below the stem and flip an angled stem upside down to raise/lower the bars.

Swapping stems: No need to unwrap the bars and remove a lever.