SENs longer routes are outliers in more ways than one; the purpose of them is perhaps at least as much to demonstrate the capabilities of the airport than anything else.
The European business-ish type routes look less random if you consider the (general) absence of competition and size of the markets for business / leisure. They are all routes of a general nature of somewhere just above BMI type routes in terms of potential business / leisure volume. They have neither enough potential business traffic to attract the flag carrier from the other end nor enough potential leisure traffic to attract a loco, but enough of both to ensure they could compete against BMI style prices and loco style frequencies.