The speaker considers abstract and functional-space descriptions useful but incomplete, noting that models are finite-sized rather than infinite-dimensional.

“Uh it's oftentimes very useful, but it's not completely true just because it we don't have infinite-dimensional functions, uh i it's not they're finite-sized. And there's a big difference between finite and infinite, right? If you have infinite dimensions, every problem becomes convex. In fact every problem becomes linear. So um on the other side with the parametric people, we say well we just have these these spline regions and that that explains everything. But if”