Mio

• Receive a random title or avatar item, up to five times a day. Each amiibo can be used once a day.

From NintendoSource

• Receive useful items or experience. Each amiibo can be used once per day, up to three different amiibo per day.

From NintendoSource

• Unlock the “M’s Consul Suit” outfit for Mio as well as Mio, Sena, and Taion costumes without jackets

Community-reported

• More easily unlock special costumes / Receive useful items and experience points

Community-reported

• Unlock randomly assigned three-minute NES or SNES game scenes. Subsequent scans change the scene.

From NintendoSource