While he leaves the story following the Battle City arc, he is a major character in the anime and, in Yu-Gi-Oh
Most collectors regret skipping them
It also picks up Professor's Research and a Farfetch'd, making it a little more reliable and slightly less susceptible to Fire-type attacks
Personally, Im not convinced that this is going to be the sleeper that everyone thinks it is, but the card already saw a significant financial spike in preorder season, so interest is definitely there
Ninjutsu abilities are not cost-effective a lot of the time, and we will still have cards that we want to cast on top of that
If you dont block it, though, your opponent gets to Mill cards and return a creature from their graveyard to their hand