Aaah, no. That refers to the Advent shop, not shops in general. In other words, old players who did the previous cross-over Sakura event can now buy the Eidolon and SSR weapon again. That is marked here and there since there was a time in Kamihime where re-run Advents did not always have their shops reset...
I removed that marking now since it is confusing in modern Kamihime.There are only two acceptable targets for Eidolon bricks: 100% Eidolons and when lacking those, Kaisers. NEVER use them on Guardians, since you'll be able to farm those eventually. Especially once purple box update comes (just like... nine months left? Yaaaay.......)
If you're a Thunder main, you might want to brick your Thunder Kaiser instead, though. Not that it's a bad idea to have a MLB Wind Kaiser, since you can use it in all elements as an ENORMOUS stat stick.