> So there _is_ a handle, but it is invisible -- and therefore it is
> not possible to move. Wouldn't you call this a problem?
I don't see there a problem - In the node tool, you can easily extract (and retract) handles:
From the Inkscape keyboard and mouse reference:
Move node handle (mouse):
- Ctrl+click retract the handle
Retracted handle is zero length; use Shift+drag to drag it back out.