Why did Oppenheimer sweep the Oscars?

Oppenheimer is Christopher Nolan's 12th film, but differs from all of his other releases. This is why Oppenheimer will be Christopher Nolan's first Academy Awards win.
Credit to ‪@Tobiet‬ for footage from her video on Dunkirk • How Christopher Nolan ...
For filmmaking shorts about Nolan, Cameron, Tarantino and co, check out ‪@anamorphia‬
Chapters:
0:40 Dunkirk
2:30 Nolan’s first biopic (but not actually)
4:22 POV
5:42 American Prometheus
6:13 Context in Hollywood