[hyperpallium]

Yes, this is the key point of microservices: it's not the modularity, nor cross-language nor "webscale" etc.

It's cheaper, because more efficient use of resources, because finer-grained. Each component of an app only gets what it needs; and the vendor can sell that unused capacity to someone else.

Geometrically speaking, finer grains pack tighter, wasting less space.

They also utilize multi-core effectively.