The core question for this discussion is 'Why is Bruce doing this to us?'. I would encourage you to go to the JupyterLab Project page from the Software Resources page and read the Commentary section. This, combined with my comments on the Software Resources page, should give you a sense of the broader discussion that is taking place in your future work world.

Another consideration that I would point out is that many of you will be heading on to other schools (Oregon State for some) who require students to use various mathematical software packages (MATLAB at OSU) that have similar structures and coding environments. I have hopes that this work with JupyterLab and Python will make that transition easier for you.