Using a Xeon for a router just because you want to use linux is a wild choice.
I wouldn’t suggest anyone buy something like this today for home use, but 6 years ago when I purchased it there were not many 10GbE routers to be had period, let alone for the price ($300 roughly if I remember correctly ). Even considering the cost of power over the last 6 years, I still come out much cheaper than if I’d bought something more power efficient new at the time.
It draws around 15W idle, going up to 30W at full bore. For comparison, the 10G rental router from the ISP drew 15W no matter what (idle or full bore routing). This is with a 10GBase-T SFP+ which probably influences the power draw vs using a DAC.
It has no issues maxing out at 9.4 Gbit routing with a single or multiple streams of iperf3 with your basic IPv4 NAT+some port forwards config.