Yes, IMO this is the right way to see it in the context of a LiveView pipeline. We’re transforming the socket except in the last step when we’re returing a tuple. And as such we should not hide this in a opaque pipe step. But I like the shortcut |> noreply() too much because it is nice visually 
More generally, a pipeline step transforms A into B which could be of a different type from A. Since the use of |> noreply() is the last step of the pipeline, it is more forgivable, even if it breaks the LiveView convention.
I just wanted to discuss the matter a little bit but I do not agree with incorporating that idea in Phoenix given the reasons you exposed.
As a side note, I’ve also used basic monadic code based on the idea of Railway Oriented Programming by Scott Wlaschin and a post on Medium. Stuff like:
defmacro left >>> right do
quote do
(fn ->
case unquote(left) do
{:ok, x} -> x |> unquote(right)
{:error, _} = expr -> expr
end
end).()
end
end
