I think ethical, in good standing, and properly managed archiving sites are never an extra, they're always welcome as long as they're good. They need to not pull shady stuff, like manipulating the archived information, that would be catastrophic.
But the reason why they're never an extra, is because I saw the embarrassing choice of Wayback Machine to blacklist Kiwifarms, which goes against the spirit of archiving. The content wasn't illegal, so that should give you enough hints about their decision-making. If they pull this stuff, what next? And which one? You can't even trust those sites to hold the information.
Another good thing could be like a bot network dedicated to find & flag other obnoxious bots, like on YouTube. That platform does not care about reports unless "big numbers", or "big person" tells them to, so maybe an anti-bot bot-network can hunt them down.