[Chaos]

Normally, a person would only be able to cast a spell twice. (6m, or 7m if doublecast).

If you get refunded 1m per cast. You can now do 7m (any water spell) > 5m (any water spell) > 3m (Splash) > 3m (Anything that costs 3m).

This now, effectively, lets you cast 4 spells, instead of 2 (or 3 with splash). Not only that, but all have their damage increased by 40% (which is technically more, but still)

You only get momentum off a weakness proc once per round. You are still getting 3 spells, weak proc or no.