I am not sure either, it is six of one and a half dozen of the other.
On one hand, if you start a thread and you then realize it was a big mistake for whatever reason (like you had your facts wrong or unintentionally started a flame war) it is nice to have the option to make it go away before you embarrass yourself any further.

And that would eliminate the MODs PLEASE HARD DELETE! thread titles that we had before the most recent board modification/upgrade.
On the other hand, some have used the OP delete option to jerk people around. One poster (who shall not be named) has made it a habit out of starting threads, getting 10-15 pages of really good discussion, then pulling the rug out from under everyone by nuking it. It is very frustrating to spend time composing posts contributing to a thread and then see them gone in an instant for no apparent reason.
However removing the OP delete option wouldn't entirely solve the problem as the OP can always just simply change the thread title to a completely different subject matter to make it difficult to find in a search, see the ESPY Awards Thread which the thread title was changed by the OP to a discussion of hard-boiled eggs after he became uncomfortable with people talking about Caitlyn Jenner being given the Arthur Ashe Courage Award:
https://forums.footballguys.com/forum/topic/684127-hard-boiled-eggs-are-tastya-rod-hits-3-hrs-vs-crappy-twins/
You might want to get some more input on this before you make a decision either way.