Kartana learning Smart Strike is rather odd. Smart Strike is supposedly performed by stabbing the opponent with a horn, and as such, almost all Pokemon that learn it have a horn. The three exceptions are Necrozma, Celesteela, and Kartana. Necrozma is pretty pointy and jagged, so I guess it gets a pass. Celesteela's head and shoulders(?) are pointy as well, so it kinda works. But Kartana? Sure, it's sharp, but it's not pointy. It's built for slashing, not for stabbing. They probably gave it Smart Strike so would have some form of Steel STAB. However, they could have just as easily given it Steel Wing, which is incredibly similar to Smart Strike in that it's a 70 power Steel move taught through TM. True, Kartana may not have proper wings, but its arms have a wing-like shape, and it would pay homage to paper airplanes and origami swans.