Yes, if you need these things, you will have to go native (although you will probably automatically benefit from unified memory).

For many many things, you won't, and then the ability to target Apple/Windows/Linux with exactly the same code, pain-free GPU access etc, that's just great. The other day I checked if I can access from the browser the 3D coordinates of my space mouse, and it just works, based on a standard Web API (GamePad API). While from Swift, it would be a hassle to setup and maintain.