I’m out of the loop on researchgate, when you say “No need” is it like an archive.is? Why is it less desirable or, if I’m reading your tone correctly, a “backup option”?
Like if someone posted a link to an archive.is version of a Wikipedia page, you'd probably prefer to get the canonical link to that content.
ResearchGate is a bit of commercial enclosure of infrastructure that is, and should be, open. Who knows, maybe it has other value. I'm not an academic so I don't know.
If I am not mistaken we can get documents without an account as well, unlike others.