no possibility to use polyline symbols

FNC TMS FNC Maps
1

Polyline symbols are currently only available for the Google Maps mapping service.
Why add symbols to TMSFNCMaps and TMSFNCLeaflet

2

The reason polyline symbols are currently only available in TTMSFNCGoogleMaps and not TTMSFNCLeafleat is that this specific feature is only available in the Google Maps API and not in the Leaflet API.