[web2py] No models vs. conditional models -- what's the advantage?

[Cliff]

Certainly we want to avoid processing unnecessary table definitions
with every request.

It seems to me that the simplest solution is something like this:

if request.controller=='foo':
  db.define_table('foo', Field...) # main table
  db.define_table('foo_one_to_many', Field(foo_id, db.foo...)...)
  ...

What is the advantage of the no models architecture over this?