@rinigus, AFAIU the OSM Scout Server Module: Fonts is currently only useful when providing Mapnik maps by OSM Scout Server.
As the Font Module is quite large (due to containing the Noto font), please clarify in its description on Openrepos (if so?):

• The Font Module benefits Mapnik users only.
• It is not used for displaying vector maps or OSM Scout bitmap maps.
• If it is a hard requirement for displaying Mapnik maps (i.e. no labels at all without it) or just enhancing the rendering of labels.

As I never used Mapnik offline maps in OSM Scout Server due to their huge size, I always wondered about aforementioned points.

P.S.: You may also consider altering the messages in OSM Scout Server, stating that the Font Module and / or Valhalla Module are "missing", as both are not needed for OSM Scout Server to work properly: I use libosmscout's maps and routing for a long time and they are working fine.