This is the first time I've heard anyone say there's no big hurry.

I guess it depends on your location and the associated amount of
traffic and ATC workload. In my neighborhood, there is ALWAYS traffic
waiting. In fact, there's too much traffic get ATC to wait for a
relay.

Also, in my neighborhood, you get a 2 minute departure window with an
IFR clearance. If you ask for 3 minutes, you still get 2 minutes. If
you ask for 5 minutes, you're told to call back when you're ready to
depart.