I think they are claiming a savings on a register file, which is not nothing, but not exactly a ton. Also they save on register renaming and scoreboards, which have some gate count.
The biggest thing that they seem to have is that they can compute an enormous number of instructions per cycle without blowing up the size of the bypass network.
If their goal is to save on register file space, they're barking up the wrong tree, IMO. The Skylake-X die[0], for example, dedicates only about 1% to the integer register file, and only about 2.5% for the floating point register file. The decoder and scheduler also take up only single digit percents.
Granted, this is a top of the line superscalar processor with AVX-512 and megabytes of cache, but my point still stands. The vast majority of the gates are in everything else: cache, execution units, branch prediction, load/store, die interfaces, etc.
The biggest thing that they seem to have is that they can compute an enormous number of instructions per cycle without blowing up the size of the bypass network.