My take on the "floating" connection between the Mursaat, Seers, and some Margonites comes from a previous discussion on this board (I think it was Quintus who proposed the idea, but my apologies for not citing the exact author).
This was, I believe, a thread regarding the ascension to godood by Kormir. The thought was that any mortal can potentially reach godhood with the appropriate knowledge and experience. The Mursatt were "on their way" to godhood, explaining their special abilities, but not quite there yet. You could view the Mursaat, and perhaps the seers, as proto gods by means of their own devices and studies - whereas the Margonties achieved similar power but via the "blessings" of Abaddon.
In short, you get the floaty ability at level 3 of the Godhood track ("Angelic", 5000 godhood pts). At level 12 ("GOD", 10000000 pts) they build statues of you.