The basic reason is to not confuse forms with inherent nature. Angels are heavenly beings, which don’t have bodies.
Actually angels are creatures who have spirit bodies in order to dwell in the spirit realm with the Great Spirit, Yahweh, their Creator. Via agency, they were fashioned by the son who was used in the creation of ALL things. (Col 1:15-17) They could materialise at will so as to interact with humans who were forbidden to communicate with spirits. (Deut 18:9-12)
It was rebellious “sons of God” who materialised in Noah’s day and cohabited with human women and actually produced children.....”the Nephilim” (literally “fellers of men”) They were gigantic in size and violent and licentious in nature, taking any woman they wanted by force. This is what resulted in God regretting that the world of mankind at that time had been brought to a level of wickedness that could interfere with his purpose in allowing the devil to rule mankind, so he told Noah, (the only righteous man in existence) what he intended to do about the situation, taking the long term view of how the process of his salvation would work out for him and his family, and how his actions would identify the circumstances that would be evident before the final end of Satan’s rulership....and the coming of the conquering King who gave his human life for them. (Matt 24:37-39)
Jesus is a man. Man has a physical body.
Yes, Jesus said he had come down from heaven, but he was given a human body so that his sacrifice would cancel Adam’s debt. That body was accepted by Yahweh and it was taken away by him. No trace could be left because God was aware of fallen man’s propensity to gather relics to worship. (as seen in Roman Catholicism) Imagine what would have become of his bones, as we see what happened to the shroud of Turin and other so called relics. Jesus was not buried in a shroud.
Another level of this inherent nature is what it means to be resurrected. ‘Re’ is your clue that it is something that is again.
A resurrection is a return to life, after time spent in the common grave, sheol/hades. (Eccl 9:5,10; John 11:11) Even Jesus spent three days and nights in sheol.
Since the Bible does not teach immortality of the soul, all the dead “sleep” peacefully until the time when Christ brings them back to life. It was God who resurrected Jesus, bringing him back to the spirit life he had before.
The fact that there are two resurrections, means that there is a “first resurrection” for God’s elect, who are transformed into spirit beings in order to dwell in the presence of God (Rev 20:6) and there is a later ‘general’ resurrection of all those in sheol/hades. (John 5:28-29) Both the righteous and the unrighteousness will come back at that time....the righteous to life, and the unrighteous to a period of judgment. The majority will be those who never had an opportunity to know God or his son.....they will get that opportunity. A thousand years to show God if they are worthy of life.
Jesus spoke against ghosts.
The fact is that there are no such things as “ghosts”. Demons are wicked spirits and these are the spirit creatures whom God has allowed to exist, only to show how defective satan’s rulership would be.
We have all been a part of the greatest object lesson mankind will ever be subjected to......showing the utter failure of the devil as a ruler, and to show the superiority of our Creator’s purpose in putting mankind on planet Earth in the first place. He will show us why free will was not a mistake.....it was a precious gift that when abused, became a curse. We had to learn by experience, how to drive it to benefit others, not just ourselves. These lessons will follow us into the new world of God’s making, ruled by those who have lived human lives....including our King.
So, where does that leave us.
We are now on the brink of entering our “Promised Land”......a cleansed earth and a new start, without the influence of Satan and his demons. These will be locked away in a place from which they cannot escape, whilst God brings the rulership of his kingdom to this earth......it’s the rulership we should have had from the beginning, but never got to experience. This earth was not designed as a training ground for heaven, but a place for material creatures to enjoy paradise conditions, and to have as an everlasting home in peace and happiness. Satan’s rule has given us the complete opposite.
There is a reason why humans have a strong desire to live in paradise......it is programmed into us to live forever in beautiful surrounding, in freedom and peace, taking care of the planet, it’s creatures....and each other.
“Thy kingdom come, thy will be done on earth as it is in heaven”......that is what Jesus taught us to pray for.....this is what the coming of God’s kingdom will mean.