A recent answer by PearsonArtPhoto claims:
New Horizons was launched at Solar System Escape Velocity, meaning it could have visited anywhere beyond Earth without stopping. It did visit Jupiter, however, that was to allow it to leave even faster, the Jupiter stop was purely optional.
In one hand, this operation shortened the wait time, reduced risk associated with deterioration of the probe over time, and reduced cost of upkeep of the mission (through making it shorter).
On the other hand, it made the flyby of Pluto awfully fast and short, resulting in only so much data from the brief closest approach. A slower flyby would give the probe more time to collect and send data. Slow enough, it might even allow for a capture into Pluto orbit.
Weighing costs and benefits - how much longer would skipping the Jupiter assist make the period to reach Pluto? And how much slower would the flyby be?