[2019] I can't understand the skill nodes, help!

These are very similar!

They both fundamentally do the same thing, though one increases the Mana Cost significantly in return for only requiring a single point of investment, and the other does not increase the Mana Cost but requires greater investment if you would like the effect to be guaranteed.

I’ll add this to the list of topics to be discussed at a future skill design meeting. The current presentation is a bit unintuitive, though admittedly I’m not how to improve it.