Stone walls are clearly stronger creations but they achieve this at a trade off. They require much more material and thus longer to create. Stone walls are also much thicker due to need to support more weight.
Brick walls are faster to build and use less overall material. They are also less resistant to splash damage due to metal reinforcing. Their intention was quick easy defence not long term siege.
If we toss in aesthetics stone walls are capable of more colors due to stone use. They are also more capable of things like rounded edges since you custom cut or place stone. Bricks are limited to their clay types and well squareness. Due to their size stone walls also present the opportunity to create walkable paths and by default ladders or stairs up to such for the inside.
I think stone walls allow us some new options to towers. We have stone towers now but they are more akin to stone keeps. I propose if or when we evaluate stone walls we add a corner tower option for stone walls. Either square or round they can be nice addiitons.
To answer another question recently about kingdom level buildings. I would place stone walls as a kingdom level structure. They take more time and resources and you are litterally creating a castle. It would also make for an interesting perk to grant to loyal citizens. Only a King/Queen could grant permission to build such massive structures. So we would gain a new kingdom level permission. Everyone else could only build lesser walls. All hail royal authority.
