To me, the biggest distinctions between the two models are display size (13" vs. 15") and storage (256 GB vs. 512 GB). While there are other distinctions, those to me seem the most meaningful.
I consider 256 GB to be a practical minimum for internal storage. Whether 512 GB is necessary, only you would know. When you compare the cost of cloud storage to the cost of factory-installed Flash (SSD)... It may be much cheaper to buy 256 GB of cloud storage than 256 GB of additional Flash.
Display size? I'm old, so I always prefer larger displays, but the other consideration is desktop size - how much space do you have to arrange your open windows. While that matters less when doing basic web browsing or viewing full-screen video, as soon as your work/study flow benefits from having multiple apps and windows open, desktop area has a direct impact on productivity (side-by-side windows are more efficient than switching back and forth between windows).
Now, the desktop areas of 13" and. 15" MacBook Pros aren't that dramatically different 2560 x 1600 pixels for the 13" vs. 2880 x 1800 for the 15", but it's still something worth looking into. Of course, both models can support an external display - for real productivity, spending a few hundred dollars on a second display could be a better investment than spending on either more Flash or a larger internal display.