Originally Lex wanted to ignore delving into his new abilities since he wanted to focus on the realm instead. But the unexpected rise in his cultivation realm forced him to pay attention to the changes.
The first and most basic change was that with his increased soul strength, the amount of strength he could display while using the same amount of spiritual energy increased exponentially. This was a straightforward increase with no hidden complexities.
But, as a result of this increase, Lex could finally do something pretty cool. He had not felt the lack of this particular ability just because of how he was nearly omnipotent within the Inn, and had other means outside of it such as teleportation.
Regardless, now he could use his spirit sense to fly!