The benefit of wgpu is that you don't have to mess with synchronization the way you do in Vulkan and DX12. This is an enormous productivity booster.

Besides, if you pick one native API (say, Vulkan), then you're still going to go through translation layers on the platforms it isn't native to, so wgpu isn't any different. Or you can write multiple backends for different platforms, which multiplies the amount of work you have to do. Either way, saying that wgpu gives you "no added benefit" is silly.

Just like middleware engines, with much better tooling.