Sadly, I have done neither of these things, so lets see what we can get out of these cards anyway
Although Kaito enters attacking when his ninjutsu ability resolves, he was never declared as an attacking creature (for purposes of abilities that trigger whenever a creature attacks, for example)
Many other effects force you to tap cards (not just attacks), so you can use this effect to prevent strategies that disrupt your own main effects or Blockers
Just look and revel in her majesty: When I looked over the legendary options from Dominaria , I knew that Muldrotha would be my choice to lead my first Commander Deck, and note that it's also cheap too (2 bucks)
Fear of Missing Out Fear of Missing Out sees a lot of play in 60-card Constructed decks, as its a really solid playable even without the synergies
Boromir is also cheap enough that if you need to sac it, you can easily recast it soon