Why take the Captain w/ Relic blade and stuff and not just take Khan? I can't remember all the point stuff, but outflanking bikes are pretty scary sometimes.
Automatically Appended Next Post: Because of unit coherency.... A 2k army with a large amount of blast weapons and a couple lucky rolls could decimate a large part of your army pretty quickly. A
PC hit on your speeders could take out multiple ones easily.
Lucky vindicators could decimate entire units as well. I guess those are chances you take