For my two cents, I like the notion of resonance but not this execution. Tying to the Christmas score is a good idea however points spent to activate is a bad choice. As many have pointed out above. Instead why not have magic items be in catagories
Trinkets: potions and scrolls magic is already in them and they are used then discarded. Also such items as salves and dusts, possibly magical tombs of learning.
Minor
Medium
Major
All three are for activate on command, always active or items with charges that are extremely powerful (ring of three wishes, staff of power) each of these categories cost resonance points to attune to and have work for you.
Instead of item slots it is a player choice to equip what he wants as long as he has the points to pay. Possibly have them lose points in con as a downside of having to many things attuned to them showing that the low degree of magic need is pulling of the reserves of their body or have it pull from wisdom as the magical fields start to warp his mind.