Difference between a Bachelor's degree and a Master's degree in CS
From my experience in Canada, a master's is about specializing and focusing on a particular topic within the field while a bachelor's is about becoming a practitioner within the field.
If, as you state, your goal is to obtain a more practical degree then both options can do that but in different ways:

A four-year bachelor's degree will provide you with breadth in CS;
A 2-year split master's will teach you the basics of CS to allow you to focus on a particular area within CS in your master's.

If you are looking to leverage your existing Economics with CS somehow then the master's is what you are looking for because you are adding CS to Economics.  If you are looking to become a computer scientist or programmer / software engineer, then the bachelor's is what you are looking for.  You will still learn (or be expected) to program in a master's in CS but you will be less focused on that in a master's than a bachelor's.
Note that at the end of either program you will have a CS degree, but you will have different skills and its which skills you are looking to obtain that should help with your choice.