This is not the company that wants to build Keystone - so how does Cruz stand to benefit from supporting Keystone? You are grasping at straws.
To Julia Trigg Crawford, the attack sounded odd coming from Cruz, who didn't speak out when TransCanada, a Canadian pipeline company, invoked eminent domain to build part of the Keystone XL pipeline through her 600-acre farm on the Texas side of the Red River. Instead, Cruz supported the company's effort.
Cruz supports the pipeline - but where is the evidence that Cruz supported using ED for the easement on this woman's land? Is she making an assumption that Cruz even KNEW about it? Pretty weak sauce. But as has been discussed before, there can be an argument made that infrastructure projects like pipelines, power transmission lines and railroads, though technically private, are in the nation's security interest and may be a constitutional use of ED.
So long as they submit to regulation as "common carriers", they ARE a constitutional use of Eminent Domain. They are operating for the benefit of the public.