Hi @Marena,
I was just returning to the forum to see if there had been any change to the vector maps issue and saw your post.
Most of my work is done in areas with poor or non-existent data connections so offline use is what interests me...
I would like to be able to plot points and lines (a grid and a transect) as an overlay to guide enumerators to pre-defined locations. If for example I was able to style a line to have a marker at each vertex / node then this would be really useful.
Another example for my point layer is to be able to style it/them based on a 'property' of each point (assuming that it is possible to 'embed' that within the vector layer) - which would give different symbols or colours (or both). This would indicate, for example, that the point requires certain parts of the form to be filled in.
In other situations I suspect that if I could translate a series of vector layers with styling (Ordnance Survey Zoomstack, for example) this would be a more efficient storage method than converting to raster and loading as a layer in ODK. This would allow me to prepare the backdrop map on the desktop and transfer to a device, knowing that all enumerators have the data available.
To explain how I 'get round' things at the moment I produce a .mbtiles file in QGIS that creates raster tiles based on a defines area - I have full control over how that map appears through styling in QGIS so I have the backdrop mapping and my data layers with symbols and sometimes labels, but obviously this creates large file sizes if I have zoom levels that are useful for navigation to my predefined locations... Just using a single vector layer for my grid or transect would simplify things and make it easier to share assuming we can simplify how people can access these layers - see: Button to select an offline map file on the phone and move it at the right place - #2 by seewhy
Hope this helps explain potential use cases relevant to me... Of course, then I would need to learn / find a tool to create vector mbtiles...