How this card reads to you depends on how you
value life as a resource. I tend not to value it
particularly highly - I once played a black-red
storm deck with Dark Confidant alongside
both Empty the Warrens and Ignite Memories - but
I still rate this card lower overall than a Mox
despite the fact that it produces twice as much
mana. Direct damage is a thing, and creatures
have always been a thing, even before the days
when everything had a comes-into-play ability.
(Steve Menendian recently wrote an excellent
article on the history of Zoo decks on the site
Vintage Magic; it's well worth reading and may
surprise you with just how long the concept has
been around.) Of course, if you plan to win the
game before your next upkeep phase, and are
going to explode your entire hand onto the table
straight away, that doesn't matter, but I
personally don't have quite that much trust in
my shuffling abilities!