Image Training—just as its name revealed, it was a skill dedicated to aiding in one's training.
Unfortunately, despite its usefulness, there was a major drawback to Image Training.
Unless Izroth experienced physical contact with an external source, he was completely cut off from the outside world. This meant that, even with his Energy Vision Sense, Izroth would be unable to tell what was going on outside the mental space. Therefore, if he were suddenly attacked, there would be no way to know until the damage was already done.
Of course, Izroth used Image Training before in places like his Mystical Realm Palace, which was a safe zone. However, it was not something Izroth was able to use often. After all, he had too many enemies to let his guard down while traveling outside of safe zone areas. Not to mention, even if he had no enemies, there was always a chance of running into those with ill intentions. As a result, Izroth rarely used Image Training.