Actually, a round nose won't penetrate as well as a swc will. They tend to veer off course too easily. The wide meplat of the swc creates a sledgehammer blow, and helps open a permanent wound channel all the way through flesh, while flesh tends to close back in around a round nose design, even if it has a small flat point thereby preventing loss of vital blood.

Penetration is important for sure, but so is large wound channel, and straight line penetration is top of the list for me.