While none of the widespread variants show increased mortality compared to the original strain, the Delta variant is significantly more infectious than the original strain meaning that even if you're still taking the same precautions you were before vaccines were available you're much more likely to get it today than you were then. And it's not just about whether you live or die, look up people who have "long COVID" who are still suffering significant disability for months after they've "recovered". Vaccination doesn't only prevent you from dying, it has also been shown to significantly reduce the length and severity of the infection if you do get it.