AIRlcy
the E jet 135/145 were conceived when the long term average on oil was around $40 dpb that and the scope contracts agreed with the US Major airlines limited the number of seats that could be operated by feeder airlines.
Although relatively (per seat) more expensive to run than say a D400 it is quicker point to point once you go beyond 400nm, quieter and more reliable, overhead bin space is an issue and for many passengers the size of it is just a bit too small.
The problem for bmir (apart from confusion with the now defunct bmi) is critical mass, they seem to have kept the same bmi DNA on route selection quickly followed by deselection.
They may fair better with their Norwegian affair by way of a comparatively low cost base, at least by Norwegian standards.