Ev,
I have an XV3080 and have saved my favorite patches to the user bank; this enables me to trigger them sending midi program change messages (1-128 or 0-127) from my keyboard, should the need arise. However, such units have so many sounds and patches (especially when you add the expansion cards) that 128 programs are simply not enough. On the other hand only a sequencer can send bank and program changes (at least I think...)
Final consideration: it's not easy to blend together sounds coming from different keyboards and modules; this usually takes also a lot of work to tweak the volume of all the patches to match the sounds in your keyboard.
More than in a live situation, I have found my XV 3080 extremely useful when I need a "special" sound to record a digital track.