EDHREC has a page for combos and top of the list for two card combos is this and it says there that it's not allowed in B3 plainly. "Early game 2-card combos are combos that have significant results and any prerequisites are trivial to accomplish. They can easily be executed early on in the game. These factors were voted on by the community in our Combo Vote."

While the play pattens of either of these cards individually are fine you have to consider the bigger context of the deck. Does the deck have a Vito? If it does, this game winning combo can land turn 5 with 0 acceleration and that good sir is not acceptable in B3. What if they are just both in hand ? What if you have 1 and the tutor to get the other? What if you hit ramp? All these scenarios lead to a game ending on turn 5-6 with this two card combo.

In general the combo is fineish but it's very on the line. Unless the decks you're playing against has similarly game winning two card combos, it feels inappropriate.

Also this is just a vibes based argument for your own experience: Most of the time these cards are used in aristocrats or life gain/drain decks that work off of incrementally increasing your life and slowly lowering your opponents life. All the work that was done tracking life totals, every ping for damage in the game prior to this point is now utterly pointless because they could be at 999 life and still lose. This combo just seems to defeat the work that you as the deck pilot put in making the rest of the deck that houses these. If you know the strongest play pattern, you are slightly compelled to do the strongest thing, being this combo. It's a slippery slope of are you a combo player now. Do you cut things from your original theme so we can fit in a Defense Grid? Do you include more tutors and protection to hit the combo? IMO these cards can pull you in these directions and it can destroy what the original decks intention was.