As per usual, every year StackOverflow's study highlights Python as the fastest growing language : for the first time, it is even more popular than Java. It is today the second most popular language among developers, making of it an asset for attractiveness and recruiting.
We rely on it because it is perfectly suitable for financial industry : it is the only language to combine simple use with security of the infrastructures. Moreover, its mathematical syntax makes it the perfect choice for augmenting web apps with financial components.