It's a lot easier to take specialisations in different fields of Thaumaturgy that aren't redundant than it is to do so with Evocation, which means it's takes a lot longer before the 'specialisation pyramid' to result in 'waste' refresh.
With 7 refresh invested in Thaumaturgy (irrelevant specialisation), Refinement (+2 relevant specialisation), Modular Abilities, and this power, a character gains 8 refresh worth of powers. With no actual rebate-worthy downside.
Add 6 more instances of refiment for a 5/4/3/2/1 specialisation pyramid and (assuming a relevant specialisation is at 5, and the remaining specialisations are not unnecessarily wasted - and even with that much invested, waste refresh is not necessary), the character gains 17 refresh worth of powers for their 13 refresh spent.