A department store bike is probably the most used bike out there. Kids from 3 years old to 18 years use them everyday to ride to school.
BUT since it is a dual suspension bike for $69, how long do you think it will last or how easy will it be to pedal? Is this bike going to be used off road at all? If not, I suggest getting more of a road style bike. Rear suspension on less expensive bikes add a lot of weight and are basically useless in the city. Big knobby tires are not too good for the road as they add a lot of resistance to pedaling.