Occlusion and Obstruction - Creating your own system or not?

Question

So, I am looking into occlusion and obstruction behaviour and want to understand more about it. I know that Wwise has its own occlusion and obstruction system which seem pretty comprehensive and ready-to-use. But, I also came over this video:

https://youtu.be/1uNjiSCTX1o

He basically makes his own occlusion and obstruction system in Ue4 with Wwise, using splines in the game engine.

My question in general is why is it beneficial to create your own system like this instead of using obstruction and occlusion with game-defined auxiliary sends?  Or is it beneficial? What are the pros and cons of making your own systems like this, and what are the pros and cons of the built in system in Wwise? What can this system do that Wwise can not?