That's what I'm finding. Enabling Z values in the environment doesn't seem to effect the out put of a Data > Export Data flow that won't help quickly create a Z aware copy of the data. Maybe I can hunt down a tool that will use that environment setting.
Like I described above, it's easy enough to re import points from a table and add the Z awareness then, but what would a user do who receives an existing 2d line for say trails in a park and then ants to use some of the 3d tools that require a Z aware line layer. Would they have extract the nodes, export an xy table, re import with Z values, the re connect the nodes into lines? Seems absurd.