I don't understand why Spear has Cold based spells

Hello,

I was wondering if people could explain to me why we have Frost based spells on Spear?

To me, it makes no sense for those to be there and it makes me feel like those Cold based spells should be Fire based spells that consume Endurance Charges from sources like Magma Barrier to generate additional effects.

Do you guys also feal like the Frost spells on Spears are meaningless or do you have valid builds based around those, like Frost Spear Invoker or something?