dnd 5e – Is Fog Cloud objectively better than Darkness despite being one spell-level lower?

The spells Darkness and Fog Cloud basically have the same purpose: Denying vision within an area. One does it by darkness, the other by obscuring it with fog, but the result is the same: The creation of a “heavily obscured area”.

Let’s compare those two spells:

Spell Darkness Fog Cloud
Level 2nd level evocation 1st level conjuration
Range 60ft 120ft
Duration 10 min 1 hour
Area 15ft sphere 20ft sphere

Looking at those numbers, Fog Cloud seems superior in every aspect. So why is Fog Cloud a 1st level spell while Darkness is a 2nd level spell? Why would a character who has access to both ever choose Darkness over Fog Cloud? Is there something I am overlooking?