You've got it right, for use with a PTO and or warming it up in the morning.
I used mine for winter morning warmups, use the choke to start it and then back the choke off almost instantly while holding a slightly elevated idle speed with the hand throttle, come back out in a few minutes to a toasty warm cab.
Folks often confuse the hand throttle with "cruise control" which it most certainly is not. It does not react to load and therefore anything but a perfectly level road you'll be "cruising" at greatly varied speeds, not effective. Also if you press the clutch or brake the hand throttle won't disengage, not safe.
Grigg