Needless to say Sci-Hub has been a massive improvement to my quality of life, insofar as satiating my intellectual curiosity is needed. And I'm not even a researcher.
I do wonder sometimes if it almost makes it too easy, in a way that ends up propping up the status quo of closed publishing and takes away the incentive of publishing in open access sources. Early in my career I remember discussions about publishing in closed journals, concerns that papers will be less read because people may not have access to them. In the last few years, I feel like this has gone away because it seems like everyone (among researchers at least) knows about Sci-Hub.
I mean, I still think that on the whole, Sci-Hub is a good thing for the research community and the state of the publishing industry -- it gives people access to the research and ultimately does take some money out of the publishers' pockets. But it does also make a broken system feel less broken, and thus people are less willing to actively push for change.