A self-delete option, allowable before a response, might be quite acceptable.
There is, however, the possibility that someone could post an "error". It is responded to by another poster. The original "error" post is then removed, possibly making the response nonsensical.
This happens quite often when posts are removed by the mods', but to allow it as an option might be advantageous to a mischievous poster.
Enhancing another train of thought about how many posts are removed before the poster is removed or suspended entirely: I'd like to see some kind of entry replacing removed posts. Something like "post removed by mods'", but leaving the original posters tag in place.
Then a poster might have the opportunity to have an idea about how many posts they have had removed.
It would also avoid the possibility of some responses appearing nonsensical even when the post has been removed by the mods'.