What are the pros and cons of applying for graduate study in multiple disciplines?
The main issues against such a path are the time and expense involved in doing so. Effectively, you have to complete two different sets of testing requirements, and you'll need to write two very different sets of essays. You'll also probably need to get different letters of recommendation, as the emephasis for different fields are probably not likely to be similar. If you apply to US schools, there is also the cost of applying to the additional schools in the other discipline.

Since you're an international student, it isn't likely that you'll be asked to fly in for interviews, so that wouldn't be a big drain on your time.

As for the pros, if you aren't sure which path you want to pursue, this will definitely give you more options. But other than that, I can't think of a "real" advantage to splitting your efforts in such a manner. (I guess one other exception is if there's a special "dual master's" program at one of the school's you're interested in; however, this requires reviewing the information available from each school.)