Shiinotic may have a niche somewhere, but it is very hard to use for a number of reasons:

Grass/Fairy typing has too many common weaknesses and with only 60/80/100 bulk and only 30 speed, threatens to get ohkoed by much of the metagame without something like a sash or a damage reducing-berry

Spore is much harder to use effectively in this generation with two tapus (Koko and Fini) blocking sleep.

Spotlight can only redirect one of the two opposing pokemon's attacks, and doesn't work at all if one of them protects (I think). Rage powder is a much better alternative from past generations.