These remind me of the T tail on the early Victor. The weak point is the suspension joint at the end of the T where it holds the diamond shaped cable support. Windage on the cables will be the same as on conventional pylons but now you have a single Jesus bolt holding 3 times the weight. How will they prevent lateral movement which would allow the cables to arc over to the pylon? A rigid joint could be subject to fatigue failure and will need some very expensive materials.
It is only a design competition and they are not bound to adopt them if they present engineering problems and undue cost. A pylon is the way it is because its cheap simple and reliable.