People discuss about if putting this or that secondary stat is or not better. I don't see the point in, without knowing for sure what is the best option, deciding to put only 2 stats. It might be that some points in a third stat (or even 4th) are more worth than the last ones in your chosen 2. And secondary stats are always secondary. Useful, etc. of course, but secondary. The last points are the most expensive because there is a high chance of failure and probably you'll need several of the highest materias for it. For someone who is really sure of what is his best option, perfect although expensive. If you are doubting, you might as well distribute a bit the points. It might be cheaper and also better. Anyway each one has his options.