Question: Why can't `use` be used as or within an expression?

This question is an expansion of my previous reply. 

There exist sixty kinds of statements in Maple, whose major pro​​​​portion can be used as an expression or within an expression (e.g., assignment, loop, and condition). But why is use an exception?

Moreover, since it is reasonable to think of use as a (partial) generalization (see below) of the subs function, shouldn't the behaviour of use be consistent with do/if?

Edit. Besides that, is there some workaround to do something like

  # If use can be used as an expression or within an expression, 
use x = 2 + y in 'use y = 4 in x + y end' end;
  # should return “use y~ = 4 in (2 + y) + y~ end use;” and 
(use y = 2 + x in x -> x + y end);
  # should output “x~ -> x~ + (2 + x);”. 
  # Unfortunately, I cannot find a workaround to stimulate them.

 at present? Note that the `subs` function is unable to do so, so in my opinion, only when the use of `use` is no longer limited to statements will it become a sweeping generalization of `subs`.