Would this method work on large construction sites? I don't think it is practical. For small residential sites it does work for sanity checks and documentation purposes.
Nothing will replace the due diligence needed by reviewing the staking notes and having a well trained survey crew.
I do like the orthomosaic for documentation purposes. It visually shows the location and grade checking within 0.10' if flown correctly.
I recall back in my staking days getting blamed for things not being built correctly. The surveyor always gets blamed first when something goes wrong. All that I had was my notes to defend myself from false accusations. By being able to produce a visual aid to show how things were staked correctly goes a long way in protecting the surveyor.
The drone is just another tool in my toolbox which I did not have many years ago.