The Zebra Bloon as a bloon is hardly a threat with its 2 delay for only 150 health, but the dual card effects allows for more total card draws in a single card, in addition to large Bloontonium gains. However, it's clumsy for the early-game, more often useful for the mid-game where it's more affordable and cards may be played more often.
Costing 7 Gold, playing a Zebra and Rainbow Bloon give exactly enough Bloontonium for Adora's Ultimate Sacrifice.
Unlike the White and Black Bloons, Zebra Bloon is an Uncommon. Hence, Zebras won't be a candidate for Rare Power, unlike the other two bloons.