After waiting for YEARS for DXF support with literally no response from anyone at Serif, this feels like a cruel joke to release half a feature. Very disappointing to say the least.
DXF import without export is, as tac0man said, pretty useless, so I can only assume there are other complicating factors that make this difficult for Serif to accomplish. Some clear and direct communication about it would go a LONG way toward building goodwill and managing expectations for the future of the Affinity suite. Right now, about 75% of my work in Adobe Illustrator involves both DXF import and export for product design and graphic design for things like labeling, packaging, etc.
I don't understand the purpose of building a house with knobs on only one side of the doors.