Then what about second turn card?
For a second turn play,
springleaf drum and
paradise mantle are perfectly equivalent,
Assuming the same Number of lands (18 ), paramantle(4), 0creatures( 8 ), the factor changing Is Number of cards of cost3.
The chance for the combination
1x ocreature
1x paramantle
2x land
1x anything with cost 3
is
4 cards = chance is 7.6%
8 cards = chance is 13.0%
12 cards = chance is 16.6%
Still too low. Ok I admit It Is a usefull replacement as the last called card for
Urza's saga (so in case the saga doesn't finish the game, you can still get 1 mana).
In my opinion, there shouldn't be more than 1 (possibly 0)
springleaf drum or
paradise mantle in affinity decks.
And yes I know it's tempting to Say "yes but from time to time, i can equip
Cranial Plating on second turn thanks to that". Don't do It.
Mox Opal is Better. It don't requires a creature. Ita basically free mana you can Always play in affinity deck ( to be honest, in a deck with 53 artifacts cards, the chance to not activate
mox Opal at First turn are very low, and negligible at second turn)
Note:
Why I don't count the Drum as utility card?
I'm reasoning in a combo way.
If you put 4 of them, you basically get it 1 in every 1 out of 3 games.
But to be usefull at the second turn you also need a specific set of cards, so while it is by itself a card and can provide some other utility it's best spent in the combination.
To count a card as utility the prerequisites are
1)The other cards in the combination are likely to be drawn
2) the other cards are usefull by theirselves
3) the utility Is usefull by itself.
Paradise Mantle and
Springleaf drum have not these points.
What about the combined chance?
So how unlucky you should be to not draw the combination usefull for the First turn, and the combination usefull for the second turn?
0.746*0.834 = 62.2% chance to not draw both
So you either get First or second turn Just in 37.8% of games.. too low.