>>Could it be because both the priest and deacon raising the hands represents Christ as the high priest?<<
That sounds right to me. And that’s why the “we are all Priests” wing of the liberal Catholics pushed all of us using the Orans position and mimicking the priest in the Holy Mass.
Remember the liberal Catholics will base this on what was said what I believe is in 1st Peter about being a “royal priesthood” by being baptized.