> It's still integration

In my view integration is by definition part of calculus, and requires the concept of the infinitesimal. (This is maybe semantic, but Wikipedia agrees with me in this case).

The paper shares one of the many goals of integration, which is to find the area under the curve, but you literally cannot use integration as the tool to do this here.

So, it's not integration.

A comment below calls this "numerical integration" - which I also find dubious. Numerical integration is still using calculus - you have to know the whole function - but without getting to a closed form answer.