I guess the way I see it is this;

(I haven't done really any deep reading on drivechains)

Allow it, to stress test bitcoin to see if bitcoin is the solution we all think it is or can become. Preferably let's stress test it before the dystopian future we all see coming, arrives...

Everyone, is starting to think bitcoin is the solution, for everything. Lol.

(It's the start of the S curve in my honest opinion...)

Now, what if each layer, solved a problem/s and we could only have 256 of these layers?

Layer 1 fixes global monetary policy

Layer 2 lightning fixes speed/scalability

Etc etc