It shows a willingness to die for an ideology. But if the criteria is getting killed for an ideology by someone else, that too is common throughout human history: non-Christians during inquisitions/invasions/conquests, anyone who's been killed/executed fighting a revolution... there really is nothing special about early Christians being executed for their religion.
Speaking of Christians specifically, you don't know if those early Christians were given the chance to recant; you don't know that they didn't retaliate or resist in any way; you don't know if their executions were the result of merely professing an ideology, or because of the perceived threat of that ideology to the ruling party, which are two different things.
Perhaps that's why we are non-religious.