So, notice that Solomon's big skill, Solomon's Ring, is a hit of each element to a target? There's a scaling problem with that.

Now, refer back to this:
"Character up means it's checking for the attribute of the character, with zero regard for her skills. Element up checks for the skill being used, with zero regard for the girl.
The example given in the wiki looks at Amon (the normal fire attribute version) and that skill of hers that does Fire and Dark damage. In the case of improving the attack of fire characters, since the skill is being cast by Amon, both the fire and the dark hits will be improved. In the case of improving the attack power of fire element, it's only the fire hit of that skill that gets buffed.

Why is element up considered to be better than character up? According to the wiki, the two actually factor into damage calculation differently. The former is potentially stronger because it's a multiplicative bonus, while the latter is an additive bonus. "

So if lategame wants a player to stack bonuses to a element attribute, only one of the six hits of Solomon's Ring would benefit from the given element being stacked. And if you instead stack bonuses to characters of one element so that all hits benefit, it scales up slower.