Definitely a great resource, but (thankfully) it's almost completely redundant in a lot of fields. I'm willing to bet almost no one in my department has ever actually used it, or even heard of it, thanks to preprint servers like arXiv where almost everyone publishes their work for free on their own (usually either before or after publishing in a real journal, but some subfields have taken to exclusively publishing there).

I think fields outside of physics and math have caught on recently; there's now a bioRXiv, PsyArXiv, and ChemRxiv. That last one, kind of surprisingly, is actually co-owned and run by ACS and RSC, two of the largest chemistry publishing companies (who, iirc, had some weird terms that initially made some people weary about using preprints at all when publishing in their journals). Hopefully more publishers can follow suit and support open access across more fields.