The biggest benefit comes when the going gets real slow like in traffic or in the dirt.
On level ground the bike will happily pull me away from a standing start at 1500rpm's, I can then let it drop back to idle and it will pull me around at 11kph with no throttle input required.
The gear ratios are closer together so finding the right gear for the situation is easier.
The down side is you will gain about 300rpm's at higher speeds.
Until I dropped to a 16 I never used 6th gear so I have not noticed any extra fuel consumption.
Some of the 19 rides in my shed
2014 V2, Snoopy
2009 Wee, Pumbaa the pig
WR450F, The Blue Postie Bike
YZ250N smoker with rego, Stinky.
Yamaha MT09 (FZ09), The Scud missile.
Club Lead not Club Med.
He with the most toys wins.
Out of my depth in a puddle.
Live life on the edge you will see more that way.
Ridding a motorcycle keeps things in balance.
At the end of each trail and at the end of each day history is made.