I generally don’t think it’s worth complicating the design to accommodate the few potato PCs left.
The meaning of this is ambiguous. The vast majority of all images in the game are pre-rendered 3D models. When these images are displayed in the game, the polygonal geometry (quads) exists in full 3D space, but it lies flat on the same 2D plane (with some exceptions, see: Early Access version 22 - #48 by InterAction_studios )
Even in full 3D games, all geometry is eventually projected onto a 2D plane. CIU performs some of these projections separately and ‘bakes’ the calculations onto a 2D result. This is how planets can appear to be full 3D but are in fact flat geometry.
In any case, from my experience most cases of poor performance are the result of poor fillrate and not a matter of “too many polygons”. So a tinting effect that’s only two polygons but takes up the entire screen (like the flash when Thundercluck appears) would be much more impactful than a few dozen particles that only take up 1% of the screen.