Background and Short Biography are very useful tools in the right hands. Or even cooler, in the wrong hands
In my last (actually most enduring) group, everybody started with almost empty characters, which personality only developed 3 sessions later.
And this was for good, for now we have:
a Human-eater Elf Blood Mage
a roguish Dragon-Choosen Warrior
a brute Shadow/Rogue
a paranoid ex-Dalish ex-Crow Archer
an angry Druid-like (with a humour of an old bear!)
a trying-to-control-himself Berzerker
a monster-shapeshifter reckless mage
a classic Dwarf Fight and his sidekick, the Coward Dwarf - now turned into NPCs as the players are gone...
But in the Game of Thrones side-campaign we're planning to play, we are already building up our characters in advance, cause we all know it better (scenario) and want more roleplaying-able PCs