I was not there in 2011, but I know some people that did transactions in the early days, and confirmations were not relevant. 0 confirmations were safe because of the lack of interest and resources put into a potential double spend attack, so you could instantly receive the coins and then spend them.

People like Roger Ver falsely sell the narrative of this being taken away by Core devs because they refuse to  raise the blocksize, what they don't get is the fact that 0 confirmations will never be safe again, and they were never intended to be a viable way to safely spend coins, even satoshi said so.