According to the NEC it says that once the service conductors enter the building/structure they are required to immediately go to the service disconnecting means. That’s why they’re typically run on the outside of the building/structure. These conductors are unfused so keeping them on the outside is a good thing. The NEC also defines what outside of the building actually means.
230.70(A)(1) Readily Accessible Location. The service disconnecting means shall be installed at a readily accessible location either outside of a building or structure or inside nearest the point of entrance of the service conductors.
230.6 Conductors Considered Outside the Building. Conductors shall be considered outside of a building or other structure under any of the following conditions:
(1) Where installed under not less than 50 mm (2 in.) of concrete beneath a building or other structure
(2) Where installed within a building or other structure in a raceway that is encased in concrete or brick not less than 50 mm (2 in.) thick
(3) Where installed in any vault that meets the construction requirements of Article 450, Part III
(4) Where installed in conduit and under not less than 450 mm (18 in.) of earth beneath a building or other structure
(5) Where installed within rigid metal conduit (Type RMC) or intermediate metal conduit (Type IMC) used to accommodate the clearance requirements in 230.24 and routed directly through an eave but not a wall of a building
One could argue that once the service conductors are enclosed by the structure finish they are no longer outside of the building and are therefore only permitted to be there if they meet one of the five conditions in 230.6. If they penetrate the side of the building and run into an attic, basement, garage, etc. they would need to immediately enter the service disconnect. 230.6(5) has a provision that allows for a mast to penetrate the structure and run up through an eave.