Have you noticed only Holy angels are known to do this?
I think if the power to materialize in human form were inherent to created spiritual beings there would be accounts of the fallen spirits using it to cause division in human affairs. I think when humans are really holy angels it is necessary to convey the message God has tasked them with. If so, then God provides the material form His message requires.
Good day, Benadam!
There is indeed is an account of those fallen spirits who defiled themselves and corrupted mankind, found in the prophecies of Enoch and which was the major reason for the flood.
"Now Enoch, the seventh from Adam, prophesied about these men also, saying, “Behold, the Lord comes with ten thousands of His saints, to execute judgment on all, to convict all who are ungodly among them of all their ungodly deeds which they have committed in an ungodly way, and of all the harsh things which ungodly sinners have spoken against Him.”
The angels who sinned by taking wives from the progeny of men: (An excerpt from Enoch)
It happened after the sons of men had multiplied in those days that daughters were born to them, elegant and beautiful. (see Genesis 6:1-2)
And when the angels, the sons of heaven, beheld them, they became enarmored of them, saying to each other: Come, let us select for ourselves wives from the progeny of men and let us beget children.
Then their leader Samyaza said to them; I fear that you may perhaps be indisposed to the performance of this enterprise;
and that I alone shall suffer for so grievous a crime.
But they answered him and said: We all swear; and bind ourselves by mutual execrations, that we will not change our intension, but execute our projected undertaking.
They all swore together, and all bound themselves by mutual excrations. There whole number was two hundred, who descended upon Ardis, which is the tope of Mount Armon.
That mountain, therefore, they called Armon, because they had sworn upon it and bound themselves by mutual execrations.
These are the names of their chiefs: Samyaza, who was their leader, Urakabarameel, Akibeel, Tamiel, Ramuel, Danel, Azkeel, sarakuyal, Asael, Batraal, Anane, Zavebe, Samsaveel, Ertael, Turel, Yomyael, Arazyal. These were the prefects of the two hunder angesl, and the remainder were all with them.
Then they took wives, each choosing for himself; whom they began to approach and with whom they cohabited; teaching them sorcery, incantation and the dividing of roots and trees.
And they conceiving brought forth giants (Gen.6:4-6) whose stature was each three hundred cubits. These devoured all which the labor of men produced; until it became impossible to feed them;
When they turned themselves agains men, in order to devour them; and began to injure birds, beasts, reptiles and fishes, to eat their flesh one after another and to drink their blood.
Then the earth reproved the unrighteousness.