It's not necessarily the wrong choice for their use case but this explanation is a little misleading. Vulkan and DirectX 12 were designed to reduce the overhead

It's not necessarily the wrong choice for their use case but this explanation is a little misleading. Vulkan and DirectX 12 were designed to reduce the overhead of draw calls and to enable multithreaded dispatch. That makes it feasible to render more objects with more state changes but the efficiency benefits still apply (in theory) when rendering fewer objects, particularly on a multi core CPU. Wasting less CPU on rendering API overhead is always a good thing - if you don't use the efficiency gains to render more stuff you can use the spare CPU for something else like better physics. Both APIs are harder to use however and it's quite possible to end up less efficient than older APIs by using them badly plus current implementations can be poor, especially on mobile, so there are still good reasons not to use them.