Here's our usage: https://github.com/FRRouting/frr/blob/master/lib/privs.h#L14...

  #define frr_with_privs(privs)                                                  \
          for (struct zebra_privs_t *_once = NULL,                               \
                                    *_privs __attribute__(                       \
                                            (unused, cleanup(_zprivs_lower))) =  \
                                            _zprivs_raise(privs, __func__);      \
               _once == NULL; _once = (void *)1)

This gives us a block construct that guarantees elevated privileges are dropped when the block is done:

  frr_with_privs(privs) {
    ... whatever ...
    break;  /* exit block, drop privileges */
    return; /* return, drop privileges */
  }

We have a nice macro for acquiring locks that only applies to the scope:

https://github.com/libguestfs/nbdkit/blob/e58d28d65bfea3af36...

You end up with code like this:

https://github.com/libguestfs/nbdkit/blob/e58d28d65bfea3af36...

It's so useful to be able to be sure the lock is released on all return paths. Also because it's scope-level you can scope your locks tightly to where they are needed.

We use it extensively in our proprietary codebases as well, FWIW. Not real open data for me to point to, but: a few million lines of C, and a handful of billion USD in revenue. If that helps weigh in on "yes, please standardize this common practice."