However, as wasteful as it might seem to have spent money on cultivating with heavenly lightning, that money isn't something that he could have avoided spending.
This is because the only reason the patriarchs of the sect allowed him to come here was that he had reached the peak of the fourth mortal coil and was much stronger than his peers. So the money wasn't wasted.
There is also the matter of his magnetic field manipulation talent, which made the patriarchs confident in letting him lead the army, but if he hadn't spent all that money to increase his cultivation quickly, he would never have been allowed to lead the invasion.
They need someone like him to lead the army because the avatars of the patriarchs can't function well in this world because of the interference of the strong magnetic fields.
