Roads for buses are cheaper than rail tracks, and significantly lower infrastructure cost is the key reason for BRT.

In opposite of rail-bound systems, buses can run on regular roads and after the trunk line split up to serve different locations. The can also run different lines on different days or different times.

Configuring lengths and doors depends on the number of stops, but also geographic conditions. Uphill/downhill and narrow curbs are better handled by 12 m buses. With longer travels, less doors give higher seating capacity, seems this bus is optimized for that.

BRT Buses do not need to be articulated by definition. Seems to be a standard 12 m bus with one double door.