"Any possibility of hostage taking was by far outweighed by the likelihood of reprisal attacks anywhere in the world."

Hostages are easily taken.
Aid workers, NGO workers, journalists, etc.
There are many precedents.
Many can still be seen having their heads hacked off on the net.

Reprisal attacks?
They are already attacking as much as they can.
All they could do is bring forward an attack, making it less likely to succeed.