A lot of that is the IO die. The mobile equivalent will have 85-90% of the single-core performance with a 15W TDP. Apple still has better perf-per-watt, but it will be a much more apt comparison.

Also the MSRP is $450. It may be a bit more expensive now, but in a month or two the price will drop.

And the AMD part had 4x the memory at 64gb. That has to help a lot with garbage collected benchmarks.