Dave Butler wrote:

If another airplane is flying an approach into the airport, you cannot
depart IFR. In those cases ATC may assign a VFR departure. You see an
avoid the other airplane until you reach your cruising altitude.

Oh, my
It's not up to me to decide whether I can depart IFR because "another
airplane is flying an approach into the airport". I either get a
clearance, or I don't.

You already have an IFR CLEARANCE, you just do not have an IFR RELEASE.
They are not the same thing.
Hence you can request a VFR DEPARTURE with an IFR CLEARANCE.
This is a spacing issue.
The controller is obigated to hold you on the ground or at a fix until
they have assurance that other IFR traffic in the vicinity (usually
around an uncontrolled airport) is clear or the requisite spacing is
attained.