When I first started using PL and was new to the control point concept, I thought an ellipse would be useful, but then I realized I could achieve the desired result by adding more control points linked to the original control point, and could also add “neutral” control points to cancel out part of other linked control points. I find that this gives me all the adjustability I need when using a control point.
What I would like is a true radial filter that affects everything inside the ellipse, regardless of colour or luminosity. If that’s what you’re looking for, there’s a separate thread where you can vote for a radial filter.