Honestly, this just seems like a poor excuse to pad a calendar of events. I see no reason why the additional items for sale are gated behind the current implementation, and judging from my searches, it seems that other people agree too.

The only interaction is simply being able to play and having enough remnants when he does show up.

What's more, bonus remnants right AFTER? Really?

Without a complete overhaul, make him "show up" (I know he's always there) every x day of the month with a bunch of different loot (create a bunch of new cosmetics/potions/whatever) like a travelling merchant. Anything gameplay affecting like potions should be an "always there" option (either permanent or every month), then cosmetics can rotate monthly.