I think this is a good idea, if for no other reason than to increase the possibility that your material will survive, no matter the future of platforms. It isn't fair that as things stand, centralised platforms containing vast amounts of user creation and data can just be trashed, if the owners decide the platform is no longer viable (Profitable). We've seen it happen with things like virtual worlds in the past, the power is simply switched off and all data is lost. In theory, as things stand, this could happen to any and all platforms. It is a good idea to use as many forms of backups of your obviously valuable material as you can, it seems to me.

Things could change, per my own analyses, if we go to Kardashev Money (As we need to, to survive), in that case, maintenance of platforms could become free, so they could be taken over by volunteers, or carried on voluntarily by existing employees believing in the good of the platform, thus saving the platform data.

But we don't know the outcome yet, so it is a good idea to try to ensure the most important data (The truth) is preserved, no matter what.