The deck doesn't play mana denial (aside from the SB B2B). This means Trinisphere doesn't really do much except against combo unless you drop it early and follow up with pressure. It buys tempo, sure, but it costs you a card and tempo to drop it and if enemy has answers to your threats, it'll end up doing nothing. It's a terrible topdeck and it's just overall quite situational. Chalice on the other hand is often good at any point in the game as it doesn't only make things cost more, it actually buys you virtual card advantage by making cards not playable.
Also do note that the deck plays 4 Chalices and 3-4 Trinket Mages and some draw. That's substantially more than most Stompy decks. This enables crafting boardstates where you have the inevitability with the appropriate Chalices; Chalice at 1 against BS decks and company, Chalice at 1 and 2 against low curve decks, Chalice at 2 against Loam decks, etc. Back when I played this deck more or less constantly, many of my wins came from just getting the Chalices down, stabilizing the board and winning while my opponent couldn't cast spells. Trini doesn't work like that.
Day's Undoing isn't that good unless you have ways to empty your hand fast. We have acceleration but our spells are ridiculously expensive by Legacy standards. You aren't emptying your hand any faster than any other deck and that makes the card strictly symmetrical making it very unreliable. You could build a version that's good with Day's Undoing but again, the power level concerns are very real as that would require playing cards that:
1) Probably don't synergize well with Chalice
or
2) Are just rather weak overall
The more all-in plan is interesting to explore. I must say though, I think the best feature of Faerie Stompy out of all the Stompy-lists has always been that it's the most robust or balanced. Back when it actually briefly hit the DTB, most of the lists were simply sleek and efficient. I always built to ensure the reliability of my deck; I wanted as few UU spells as possible with sufficient lands and both, ways to function under flood and ways to survive screw. That's why I've been running cards like Mulldrifter, Thirst, FoF, Looter, etc. Nowadays I think JTMS is the best flood prevention that's also good overall; it's the Brainstorm-that-works-under-Chalice we always wanted. If only 2UU weren't so hard to cast.
But yeah, Serum Powder + Griffin is certainly a neat combo and if you're running Griffin + FoW and Griffin + Chrome Mox perhaps with Manipulate Fate, you can get a lot of mileage out of the card. The biggest problem of the deck still is that TNN is one of the best cards we could ever hope for though and it has the absolute worst casting cost possible.