Everything said about BSO's is correct. However the majority of us are viewing these things from the viewpoint and experience of serious cyclists.
I ride a BSO. It has no suspension, but everything works as it should. It is heavy, isn't the best fitting bike in the world so why do I ride it. I ride it to town, 10 minutes each way, to the doctors, the library, the railway station and anywhere else not too far away where I am going to leave it at the mercy of the local scrotes. I suspect, that with the odd exception, this is the use that the majority of adult BSO riders put their bikes to. Like the woman referred to in the opening post of this thread. Pop to the shops for a pack of fags or whatever. Leave the bike outside and if it gets nicked get another one for £20 or off freecycle (where mine came from), the point being if it gets nicked, apart from cussing at having to walk/bus home, who cares. I would rather my Universal get nicked than my Ridgeback.