That would depend on your study and career goals. Choosing a major and a minor would imply that you wish to specialise in a particular field while also gaining some knowledge relevant to another field. In terms of your career, it could also imply that you wish to start a career in the field that you major in while gaining some knowledge that may be relevant to your future career. Since a minor requires completing fewer units than a major, you would also have the opportunity to complete elective units. This would allow you to complete units of your choice, which would be suitable if you are interested in particular units not within Finance or Business Analytics, or not within the Bachelor of Commerce in general.
On the other hand, choosing two majors would give you an equal level of knowledge in both fields (in your case, you would have equal knowledge about Finance and Business Analytics), potentially giving you additional career options, since you could technically work in either field, or start a career that involves applying your knowledge from both fields. With that being said, studying two majors would reduce the number of elective units that you can take (if any). However, if this is not important to you, then you do not need to worry about it. I would personally recommend studying two majors, rather than a major and a minor.
I hope this helps!