Tbh, I think this looks daunting. I think the caller's life is simpler with the former.

n, err := NewIPFSNode(ctx, Standard(r, false))

is simple (the Standard(...) thing is a bit weird, but otherwise straightforward), whereas

NewNodeBuilder().Offline().SetRepo(r).Build(ctx)

is not simple. I have to wonder about what the builder is, whether and when i can call Offline and SetRepo, etc.

I'm sure there's a way to do the new stuff without complicating the user's life. I would keep something like this:

n, err := core.NewNode(ctx, core.Options{
  Repo:    r,
  Offline: true,
})

n, err := core.NewNode(ctx, core.Options{
  Repo:    r,
  Offline: true,
})

Yeah, the builder is really just syntactic sugar on top of that. So i can remove the sugar

closing in favor of #1572