How is "Free Grace Theology" linked with dispensationalism?

I have a somewhat vague understanding of dispensationalism and Covenant theology, and have until now preferred the latter to the former because it seems simpler and hence more intuitive. I recently came across Free Grace Theology (FGT), which seems very appealing to me and, to my mind, focuses on the Gospel in a sharper way than either Reformed or Arminian theology. However, in watching talks by FGT people, I've noticed that they link FGT to dispensationalism in a very tight way, as if dispensationalism needs to be assumed in order to arrive at the Free Grace position. I would like to understand how and why this is the case, if it is true. Also, is FGT compatible with Covenant Theology?