One thing to remember is the main difference between the pipe bender and the tubing bender. The pipe bender basically just bends the pipe with brute force, if you were strong enough the bend it over your knee it would be the same type of force. That is why people end up kinking their metal when bending with a pipe bender vs a tube bender. If you want smooth bends with tube use a tubing bender.
Another thing to remember is that a 2" die for pipe is different then a 2" die for tubing. Pipe is measured in a different way, so the sizes do not match up. The same goes for trying to use a tubing bender to bend pipe, the tubing bender needs exact measurements to make the smooth bends so the dies probably won't match up properly.
There are exceptions to the rules, so yes you can make a cage completely out of pipe with a harbor freight pipe bender and make it look good. You won't know if it will hold up to a couple of rolls down a hill until you do it. I would stick with 1.5" DOM and a tubing bender for my cage and leave the pipe for nerf bars and other things I don't mind if all the angle bend upon hard impacts.