I just got a switch for my son for Christmas. He wants splatoon 2 and I'm wondering what's the point of the ambiios. Can someone explain. Should I get him those too?
Different uses in different games, usually unlock additional characters/content corresponding to that amiibo as far as I can tell(never got into them myself, spend enough money on the system and games, don't need to spend more on those )
The splatoon amiibos as far as I can tell are only used to save outfits in splatoon 2 for when you play it on another console. They aren't really needed to play the game nor do they enhance the game in any way.
As stated above, different games do different things with amiibos. Mario kart 8, some amiibo will give you different outfits for the mii racer character. Zelda breath of the wild you can get some items with a few exclusive items to the zelda series amiibos.