Interesting. You are the first one I have heard with experience reloading steel. i am surprised to hear that it is so simple. My No! comment was based on a fair amount of reading on the metallurgy related to what make brass such a great choice. It needs to be ductile enough to deform under firing pressure with rebound enough to extract and soft enough not to work harden too much when you resize it. My impression of steel cases is that they were a cheaper solution to replicate the same properties to give a cartridge that functioned in guns designed around the properties of brass cases.
You would think that steel's extra strength would make this simple, but I don't think it is that easy. Making the cases thinner gives you the flexibility on firing, but my understanding is that it comes with a trade off of much faster work hardening of the thin case mouth when opened and then crimped to hold the bullet. Add to this that the dies were designed around brass properties for rebound etc. I would think you would get head separation as the case stretches repeatedly to reach the breach face. Probably less of an issue with straight walled cases.
Given the level of subtly in case properties, I will stick with brass as long as it is plentiful at my local range. I am impressed about how deep into all this the benchrest shooters get trying to get the last little bit out of a load. Me, I just like to shoot stuff!