1) Provide security to the network, which you possibly threaten if you're in DeepBit.
FTFY
2) Make a profit off of it, lol 3% fee.
I agree but other pools have stale shares, downtime, weird score formulas, longer payouts, etc... each has it's own strong points.
Nah, he was correct the first time.
2. To be a source of danger to
Regardless if an attack occurs, mining in deepbit increases the ease of such an attack and is dangerous for the network.
You buckle your seat belt when you drive, because you don't want to threaten your safety by not buckling it. You may never be involved in a wreck, but you take precautions against danger in case you are.