I was always impressed by the Smart's safety rating and it's overall function as an urban commuter, but don't care much for the styling which is critical to what I drive as well as handling and comfort. I think the Smart scores ok in the comfort category. I wonder if Smart sales never really kicked off and then declined because of no advertising and or marketing campaign? I have never seen a TV commercial or print advertising for the Smart. Perhaps targeted to urban dwellers. I have a neighbor that owns two Smart for 2's and likes them as do most owners.
Look a little further into the Smartcars safety rating. Look to see why it took 4 years to get passed in the US after it passed in Canada. Mercedes lobbyists convinced the gov to change the US crash test from head-on to a 45° angle. They argued successfully that a 90° crash was not a reasonable assumption, as they poured money on the problem. The test it passed in Canada was head-on, but at a much lower speed. The battery for the all electric smart is made by Tesla.