AFAIK, these features can also be found in higher end alarms, i.e. Clifford. Yong remote off, i think that's basically a turbo timer. Yong remote on naman, is useful for cold climate countries na kelangan nila painitin ang engine nila for a while. Di yata sya ganun ka-useful sa atin.

As to prevent carjacking, since integrated 'to sa alarm at umaandar ang makina mukhang mahirap gawin...unless pwede ka mag-activate ng alarm/remote off function while your engine is running.

That's the extent of my experience with this. There may be other who can give more enlightening ideas..