I think having a noscript site like old.lemmy.sdf.org available could only be a net positive, I can’t imagine that it would hurt to have it as an option, as long as it’s not too much work to keep it running.

I agree with these other two posters. Why not wait and see what Threads even ends up doing before they’re potentially defederated? Obviously, Meta wants to find some way to make money from the Fediverse, but will it actually affect users who aren’t registered on their servers? Let’s see.