Well, it does preserve the scientific editing system to a large extand so yes. I would prefer there is no embargo at all, because I'm paid with public funds and I don't see the point of paywalls, but I get the Government has a to be gentle to the international editing scene to some point.
Publishing articles typically requires you to submit manuscript that (upon acceptance) will be prepared for publication by the journal. For this final version, authors have to sign over their ownership rights to the journal, and they're usually not allowed to publish this version on their own website. However, it's common practice nowadays to publish the manuscript version on a preprint server, which are open access and allow other people to read it, even if their institution doesn't subscribe to the journal.