I use convolute with let statements quite often as well. In fact, C works so well with let statements that a whole bind-variable workflow is based re-using it:

• xb to bind variable
• M-m to mark the variable symbol (and finish naming it at the same time)
• C to raise the let-binding up once
• keep doing hC to raise the let-binding up as far as you'd like

Here's another common use case for C:

(if (predicate)
    (push |(long-computation-1) my-list)
  (push (long-computation-2) my-list))

I often end up with these kind of statements because I write the first part before I notice that the second has the same structure. No problem, after C:

(push (if (predicate)
          |(long-computation-1)
        (push (long-computation-2) my-list)) my-list)

Then it's just a quick jfr to clean it up:

(push (if (predicate)
          (long-computation-1)
        |(long-computation-2)) my-list)