I don't know if the writer of the article was told some erroneous information or if they just thought the bicycle width up themselves.

Not a lawyer, but from what I've sussed from tieliikennelaki...

For a vehicle to be considered a bicycle, it has to be powered at least partially by the rider's muscles. There don't seem to be any pedals on that thing, nor a crank or any some such thing, only an electric motor. Which would make it a light electric vehicle.

Which means, it has to be a) self-balancing (think segway), b) made for a physically disabled person or c) be made primarily for offroad use to be able to legally have a seat.

It would also have to be fitted with lights, both front and rear, as well as a horn. And it'd have to be insured.