say you sculpt a brick wall. It looks amazing. It took you 2 hours. A week later it is decided that the bricks need to be 50% larger. A week later, the size is good, but we want 75% of the bricks to be damaged. If you sculpt them each time, your soul is dying and somebody is losing money fast. If it's setup as a procedural…
Designer is not a quick way to do things actually and final substance may be so complex you could hardly able to tweak anything in the beginning of the node flow. It's often like a house of cards. You touch something and it no more looks real. Especially with the scale of things since you may need to size in sync every…
nothing stops you using both sculpt some bricks, bake heightmaps and use designer to lay the heightmaps out Designer is not well suited to creating very specific shapes - if you need one of those, use a tool that is well suited to the task and use designer to handle the bits that it is good at
I'd say anything that is reusing a lot designer is king to build the trim sheets or tilables. Any unique asset will profit from sculpting. That being said, nobody is stopping you from using designer generators, textures etc to texture your uniquely sculpted mesh