Usually when green spells put a land in your
hand with a chance to "upgrade", the upgrade is
putting the land into play. Not here-- a
delirious Traverse also has the option of
getting a creature. This would be more
impressive if Traverse was an instant. Then you
could get a flash creature during combat, or a
Madness creature in response to a discard spell.
Here it's a solid way to find some more pressure
in the late game or thin your deck early, which
is certainly good enough.
It's a . . . rare Rampant Growth variant? At
least, that's what it looked like when I first
saw it. Of course, in a deck that can enable
delirium, it's actually a spell that's quite
nearly as flexible as the old-school Vampiric
Tutor, which I never thought I'd be saying in
the modern era. And since the number of decks
that can enable delirium is surprisingly high -
many midrange and control decks play more than
four different card types because there are just
that many cards that support their plan - I
expect this will turn out to be quiutea popular
card.