Soul energy was indispensable when he used this map because he needed to simulate battling with these Primordial forces, and he had no way of expressing their powers unless he had a source of energy that could become anything.
Only with this power would anything he was doing here be accurate, of course with his powerful mind he could simulate the effects of these Primordial powers well enough, but there would always be a margin of error no matter how minute, and when this tiny error was placed in a battlefield that spans countless dimensions, even a tiny error would transform into something apocalyptic, soul energy made sure he was accurate, one hundred percent of the time.
Rowan was not too concerned with the technicalities of the powers being displayed here, especially by his enemies, although they were precise, it did not mean that it would serve him well if he was to copy it, the whole purpose of this map was to find weaknesses, not more weapons or spells.
