Because it is not good for tangling.
For example, tangle the bellowing src block, the tangled source code file
will has `(ref:hello)` too.
```
#+begin_src emacs-lisp :tangle "data/code/src-coderef.el"
(message "hello, world") (ref:hello)
#+end_src
```
The tangled source code file looks like this:
```
(message "hello, world") (ref:hello)
```
This absolutely is not a good idea.



And after a test, I found I can't tangle the bellowing src block:
```
#+begin_src ruby :dir "data/code/src-coderef.rb"
puts "hello, world" (ref:hello)
#+end_src
```
Even with a comment char prefix:
```
#+begin_src ruby :dir "data/code/src-coderef.rb"
puts "hello, world" # (ref:hello)
#+end_src

```

[stardiviner]           <Hack this world!>      GPG key ID: 47C32433
IRC(freeenode): stardiviner                     Twitter:  @numbchild
Key fingerprint = 9BAA 92BC CDDD B9EF 3B36  CB99 B8C4 B8E5 47C3 2433
Blog: http://stardiviner.github.io/

On Fri, Jan 26, 2018 at 4:19 AM, Nicolas Goaziou <mail@nicolasgoaziou.fr>
wrote:

> Hello,
>
> "numbchild@gmail.com" <numbchild@gmail.com> writes:
>
> > I see. Seems current ob-core.el can filter out the `src-coderef`.
> > Like the following:
>
> [...]
>
> > My wanted feature is simple, just `(insert (concat comment-char
> > coderef-format))`
>
> Per the above, may I ask why you do need it?
>
> Regards,
>
> --
> Nicolas Goaziou                                                0x80A93738
>