Yes. Other reasons include ergonomics of handling and using the weapon. The British even had a top loading magazine on their Bren guns so that they could lay closer to the ground while firing. In the early portion of WWII our Marines were issued Johnson light machine guns with the magazine inserted on the side, similar to the British Sten gun.
I fired Bren guns while I was in Army Cadets and Reserves (Canada). I had some trouble with the sights on the Bren, which are offset to the left; because my left eye is dominate.
As a side note, it wasn’t a British idea, the Bren was a copy of the Czech VZ-30.