I'm also building mostly with stone right now, but have some design elements that require reinforced wood beams for sure. One is a tower for our doorstep and sitting room on the next floor. There's a "keyhole" type of opening between the stones at the front of the tower, then the door to the castle is on the other side of the doorstep. Here's a progress picture to help explain what I mean.

https://steamcommunity.com/sharedfiles/filedetails/?id=2555156551

The next row I built required support for the stones above the opening. I built a frame to hide the beams inside the stones and keep the stones anchored even though they appear to float above the stairs to the doorstep. This way, I can complete the tower.

The iron beams are useful for building with wood (regular and core wood) and with stone. I don't think they need to be buffed because they are so valuable (as is) to all types of building materials and designs.