The Sneak rebate is the entire pick. At this is a card you cut, so the real question is whether any TMT deck casts it at
often enough to matter, and the five-pair structure makes the answer harder than it looks. Sneak wants an unblocked attacker you are happy to bounce, but none of the supported pairs (RW, WB, BG, UR, GU) is a dedicated black tempo shell. The closest fits are WB and BG, and both have the same problem: WB legends and BG Food are midrange goodstuff decks attacking with bodies they want anchored to the board, not replayed. For them the rebate clause is a tax, not a feature, and the four-mana floor is the rate they actually pay.
That leaves a narrow case. If your WB or BG deck leans on cheap evasion (a Menace one-drop, a flyer you would gladly recast), Splinter's Technique becomes a real consideration around P1P7 to P1P8, behind the removal and the on-rate Sneak creatures. The tutor target has to earn the slot, and in a format where the ceiling is the mythic legendary Turtles or Shredder, Unrelenting, you only want this when one of those sits at the top of your curve. Find your bomb and the floor stops mattering.
The punisher is your own combat math, not a removal spell. Sneak resolves during declare blockers on your own turn, so you commit to the tutor before you know what the opponent held back. Bounce into a blowout and the card you searched for arrives a turn late and a creature short. That is the failure case for the average TMT deck. It only stops being a trap in the deck that genuinely wants to recast the body it just swung with.

