Why use pipelines?

Hi there,
I’ve been trying to figure out why I should use a pipeline…
I started a project a couple of months ago on the default 3D template (NOT a pipeline), and just upgraded to the LRP today. However when I updated I ran into a few problems with my post processing.
For one, Ambient occlusion wasn’t supported. Neither was Motion Blur…

So can anyone tell me why I would even use a pipeline? I can use post processing without it (even get AO and Motion blur). I even had to remake some of my level in order for the texture to not be pink…

Lightweight Render Pipeline (LWRP)
You can use LWRP across a wide range of hardware, from mobile platforms to higher-end consoles and PCs. LWRP uses simplified, physically-based Lighting and Materials to achieve quick rendering at a high quality. LWRP uses single-pass forward rendering
, for optimized real-time performance on several platforms.

High Definition Render Pipeline (HDRP)
HDRP targets high-end hardware like consoles and PCs. With HDRP, you’re able to achieve realistic graphics in demanding scenarios. HDRP uses Compute Shader technology and therefore requires compatible GPU hardware.

You can find more info here: Unity - Manual: Scriptable Render Pipeline fundamentals