Jake wasn't the dithering type anymore. It was a defect that had been ingrained in his character in the past, but the intensive training of the last Ordeal had definitely corrected this bad habit, as well as his lack of self-confidence.
There was no point in thinking about what else his Aether could have been used for. He had several choices, and he decided to choose power without hesitation. He only had a hundred crystals and about 1600 pts of Aether at his disposal. Therefore, his possibilities were limited.
If he could get more crystals, he would have produced 100 Red, Orange and Yellow crystals, which would have given him enough to immediately double his Strength, Agility and Constitution in case of danger. Unfortunately, that was not possible.
It's been a long time since the last faceslapping scene. :D
If some people wonder why Lamine and Yerode are so weak, it's a question of stats. In hand-to-hand combat, they are as dangerous as he is, and even more so with a gun. But their brains are not their strong point. Their Ordeal rewards have been used for more concrete benefits like Aether Skills but their intelligence hasn't improved much, even if after this encounter, they won't make this mistake again.