With many formats revolving around 20 life, dealing 10,000 damage is way overkill, and it's most likely there for flavor since Final Fantasy 's Jumbo Cactuar also has an attack called 10,000 Needles that deals that much damage to one party member
If you don't have plenty of artifacts this is pretty mediocre, but once you're casting it for 5 or less you're going to be pretty happy
The ninjutsu ability can be activated during the declare blockers step, combat damage step, or end of combat step
Your sideboard does come in handy at least, as it features an array of board wipes and removal spells
Theres an infinite combo in this precon using Walking Ballista, Hardened Scales, and Gatta and Luzzu, which results in infinite damage to any number of targets
That said, getting a flashback option that will slide comfortably into decks that want to keep wheeling and filling the yard is nice, and Snort will do that for you