It's mostly not about performance, but about getting rid of legacy cruft that still exists in modern 3D APIs to support older GPU architectures.
Getting rid of cruft isn't really a goal in and of itself, it's a goal in service of other goals. If it's not about performance, what else would be accomplished?
Getting rid of cruft isn't really a goal in and of itself, it's a goal in service of other goals. If it's not about performance, what else would be accomplished?