It's horses for courses.. and its probably fine for what all basic archicad uses are now expected to do
If clients want accuracy, they are better off going to an environmental engineer, most use poorly presentated FEA 2D. If you want to step it up ANSYS, Comsol, Adina all do 3D multiphysics (FEA) and costs 20x...but clients luv the presentation. LOL, its like 20 years ago when clients first saw Archicad/3D, they couldnt get enough, now its the norm. The great thing about multiphysics is you can write your own (Silver bullet) Pdes/Equations and purpose made apps and deliver them with absolute precision, like customized medicine
Ill see if I can put up some of my WDs up