I remember trying to run a piece of software in the past that actually required Kickstart 3.1... Can't for the life of me remember what it was, but I had 3.0 ROMS at the time in my 1200 and could not run that program. You could softkick 3.1, but why not treat your Amiga to a nice set of 3.1 ROMS?
Also, by having real 3.1 ROMS as opposed to soft kicking, you would shave a second or two off the boot time from cold boot, due to the Amiga not having to load the ROM from hard disk.
