The program is in very early development, so the workflow is largely incomplete. There are A LOT of things that need to be fixed/added before I can offer it to the public. So how the program handles several curves together is not decided yet. The current version groups curves by layer, or the user can switch to the 'select' tool and select multiple curves within the layer to manipulate.
Your points are quite valid and echo what I have been thinking about this past week.