The major strength of Drake's fruit is that it allows him to turn into an allosaurus, a large and powerful predator from the prehistoric era. This makes this fruit well-suited for combat purposes, since carnivorous Zoans are said to be fiercer fighters than non-carnivorous ones.
This fruit has no known weaknesses, aside from the standard Devil Fruit weaknesses.
While in full allosaurus form, Drake's own size increases, making him bigger than a Pacifista, and he retains this size while in hybrid form. He is also granted a strong biting ability that can even damage the heavy armor of the aforementioned Pacifistas, which are said to be stronger than steel. His tail is also a powerful weapon, capable of slamming people with great force.
The following events are Non-Canon and therefore not considered part of the Canon story.