It is not a self-praise at all. It is Allah who is addressing him. How could he call it a self-praise? Because the translation is that laulaka lama khalaqtu laflaq. O Muhammad, if you were not to be created, I should not have created the universe. That you are the final goal, the summit, the ultimate for the reason of creation. That is the meaning.
So no question of self-praise arises because it is not Huzoor-e-Akbar sallallahu alaihi wa sallam himself who is saying this. It is an address from Allah. Yes, sir. How would you explain the Hadith-e-Qudsi? That I will do. Yes, please. Hadith-e-Qudsi is a term applied to all those traditions in which Huzoor sallallahu alaihi wa sallam has known to refer to Allah as his having told him this in particular or even without referring to him where he has mentioned such subject in a manner as would not be possible for him himself to say that.
And the underlying meaning of that, whatever he has said, directs one, I mean makes one believe that it was Allah who told him originally. For instance, according to the scholars, all the prophecies which belong to the future should in essence be called Hadith-e-Qudsi. Whether he has said it in so many words or not that Allah has told me, but whichever, whatever he has said, if he could not have said it from himself and it was Allah who had told him or if there was internal evidence or external evidence, in both cases that tradition would be labelled as Hadith-e-Qudsi.