short spines are a must for good performance. Also the lexicon makes me understand a short is better.
Short splines still does not affect the performance ingame. In theory they produce more polygons in the final mesh, so they decrease the performance ingame by 0.00001 FPS or something like that. I still don't know, where you got the connection between my statement and the performance? If there are some tutorials or lexicon articles, which may be misunderstandable, we will edit them.
The conclusion is: Using short splines will affect the stability of the Map Editor in a positive way. The integrity of a short spline is higher than the integrity of a long spline. If you use long splines and big polygons, you will likely get more errors in the terrain or they lead to a miscalculation of some properties as it was in the thread you got my text from. So there are benefits when using short splines and that why we always mention it. But there is no connection between short splines and the performance.