I use my clutch for range changes and PTO engagement, mostly because the book said too. As for the lift arms, if you set the mower deck cutting height to "top" the mid mount lifts will stay up while your 3 PH is busy with other things.
The book tells you to use it for shifting in and out of 4wd also. It doesn't seem to do much though. Seems like if it doesn't want to go in or out of 4wd moving the steering wheel (straighten front wheels) or going forward a bit helps more. Also going slightly forward or back then shifting seems to help more with gear range changes when it's stubborn then the clutch does. I think it is mostly useless and is a decoration except for maybe the PTO and I can't speak for that since I don't use my PTO yet anyway.
One thing I have used the clutch for is to push it in while rolling very SLOW forward and make a gear range or 4wd change. There is no grinding and it goes right into gear. I'm usually not in that big of a rush though.
