I don't see how the airport is shuttered any longer when you issue a "hold for release" clearance before the airplane is started followed by a release when #1/ready to go than if the entire clearance is read at that point. Further, it gives you more "heads up" time to sequence the departure in with the arrivals. Is there something I'm missing?
Issuing a hold for release instruction with an IFR departure clearance does not shut down the airport to IFR operations.
As for "heads up" time, that can hurt more than it helps. I'll use an example I learned first hand, about a week after I certified on my first sectors at the TRACON.
A Hawker departure informed me he would be ready in 15 minutes, and wanted to copy his clearance while waiting for passengers on the ramp. I wanted to "help." I read his IFR clearance and issued a hold for release instruction knowing that he'd likely depart in 15 minutes.
That he'd "likely" depart. Nothing there says he has to.
In accordance with Murphy's Law, 15 minutes later a BeechJet checked on arriving at the same airport. I began vectoring the BeechJet for an ILS approach rather than a visual, thinking the Hawker would call me in any second. Turned out the Hawker stood me up as I cleared the BeechJet for the approach. I tried raising the Hawker on our RCO, nothing. Now I had another concern: the Hawker's flight plan will soon time out of the computer system, thus deleting the flight plan.
Because I had issued an IFR clearance, I had to amend the proposed departure time every few minutes to ensure the flight plan . There was no "expiration time" for the clearance, and I was starting to wonder how long I would have to amend this aircraft's proposal time.
Seventy minutes later, I got my answer as the Hawker called holding short of the runway, ready for departure.
I don't issue hold for release instructions to aircraft who aren't yet ready for departure. I'll gladly relay any routing changes, but I withhold issuing the IFR clearance until the pilot informs me he or she is ready to depart.