This speeds up early to mid-game plays, as you can cast any Hydra you want for cheap while you spend your mana ramping up into big-mana territory
just be wary of multiples in your opening hand
Ideally, you'll add in Tymna the Weaver here since you are attacking for life gain, and now cards and something to use that life gain in card draw
However, Caduceus goes back to older wording only requiring 30 life
Prosperous Innkeeper and Tireless Provisioner produce tokens, Academy Manufactor multiplies them, and then Hazel's Brewmaster gives those Food tokens strange and mysterious powers (beyond merely gaining life, of course)
Although Yuffie enters attacking when its ninjutsu ability resolves, it was never declared as an attacking creature (for purposes of abilities that trigger whenever a creature attacks, for example)