It looks like you’ll be able to unlock Super Smash Bros. Ultimate characters with little to no effort. According to an official Best Buy Canada listing, fighters can be accessed by simply tapping their amiibo. The following description is attached to the Wolf amiibo; similar wording has also been spotted for newcomers Inkling and Ridley:
Access a whole new level of fun and smash the competition with this Super Smash Bros amiibo. A former fighter in Andross’ army, the Wolf now leads his own mercenary team, and he’s not one you want to cross. Simply tap the amiibo accessory to the NFC touchpoint on your game system to unlock this Space Pirate.
Source: Source Gaming @AllSourceGaming