HI-RES Plants are specifically made to be used for very realistic rendering inside Archicad due to the high detail of the model 3d and textures; they are also compatible with Cinerender providing bumping and reflection channels. These plants are 3d models that can be scaled in 3d. These plants don’t have a symbolic view in elevation.
2D-3D Parametric Plants are 3d models always different one another generated from a GDL algorithm; they have a lower level of detail with a low number of polygons; these plants have a symbolic model for elevation; these plants are better to be used for drafting drawings, but also for conceptual rendering and BIMX.
At the link below you can download 2 trees of both versions for free (2D / 3D and HI-RES) so as to test the differences before purchasing: Download free trees