Good Day All.
Fred T's explanation is valid, but more of a fringe benefit than standard policy, because being such low mass engines, they spool up from idle very quickly.
If I remember correctly (manuals in the attic now) the manufacturer's SOP was to deploy the tail brake at 100 feet on approach. This procedure was designed to wash off 8 knots by the time touchdown arrived. Without the brake (e.g. when the auto-deploy was u/s [very rare] and I forgot) it was quite slippery and didn't want to land.
Procedure was to pull the speed brake lever (to the left of the thrust levers) to the flight detent at 100 feet. The brake had a maximum rate of extention/retraction so even if you whipped the lever back, the brake moved at a civilised rate. This also armed the spoilers, which deployed on touchdown. As a back-up, we pulled the lever through to the ground detent on landing, in case the auto spoiler deploy failed.
On a steep approach (London City for example) I seem to recall the speed brake was out all the way down, and Fred T's comment becomes more relevant as the idle RPM necessary to keep the speed down would cause a slight delay to spool up in the Go Around.
Regards - musang