What's the difference between the Planner's Kit and the Supply Closet?

Planner's Kit: free, automatic, for special items (Toppers, Keys, tools). Items there are always usable — drag them out anytime.

Supply Closet: optional storage for ordinary chain items. Items inside are inactive — they can't fill orders until you drag them back to the board. One sentence to remember: nothing acts from the closet; everything in the Kit is ready to act.