I use whatever comes my way free or cheap.
Most everyone who knows me is aware of my groundhog obsession. Anytime they come across free broadheads they give them to me. Replaceable blade types work just as well as the more "trad" styles.
Many bowshoots will have swap meets where you can buy/sell/trade most anything. My best purchase was 4 dozen MA-3's & Bodkins for $5. I am always on the prowl for cheap hog heads.
Pulling broadheads out of a groundhog is not easy. When the broadheads are cheap it's not a hard decision to just unscrew the shaft and let the hog keep it.
Your are right, a blunt will normally just bounce off. It takes a broadhead to kill them.
I was hunting the other day and saw a freshened hole. There in the dirt pile was 1/2 an aluminum arrow with my rusty Bodkin. A big hog took it down after a good hit last summer. When a new hog moves into a hole it will push out all the old arrows.
My 200th kill took the arrow down the hole and I was bummed about it. I wanted it for my collection. I came back a year later and there was my arrow, pushed out after spring cleaning. Cool.
When you lose every other broadhead down the hole you might as well use something cheap.