33:33 says all that God desires to keep away from the Household of revelation, is uncleanness, thereby bestowing all value and blessings in the creation and that he desires to only purify them a certain purification which means they are always at the highest level of blessings and purification, and there is no limit to purity, Imam Zainal Abideen (as) teaches regarding the Angels to says "blessings that will increase their purity on top of their purity".
So Ahlulbayt (as) are bestowed constnatly unique level of purification, which means, they are the highest level with Mohammad (pbuh&hf) and the phrase "God only desires to make the uncleanness be away from you O people of the family" also implies that God desires to bless them with no limit and he has commanded creation thereby to help "Indeed God and his Angels bless the Prophet, O You who believe, bless him and salute him a salutation".
According to the Prophet (pbuh&hf), the proper way to bless the Prophet is to bless his family with him and to salute him salutation is to connect their position with that of Abraham and his family and connect that to God's Affair of Majestic Praiseworthiness.
It has an allusion to the words to Sarah regarding Abraham, herself, and her chosen family who are the chosen family of guidance of that time, "God's mercy and blessings upon you O People of the Household, indeed he is Majestic Praiseworthy".
Indeed the Angels blessed the family of Abraham, and likewise, when the bless the Prophet, they blessed his holy family as God only desires to keep the uncleanness away from them.
And Ahlulbayt exceeds all purity found in creation, as God constantly desires to purity only them a certain purification.
There is no comparison between that and being given the good news of paradise on the conditions one remains steadfast and on the course of God's favor.