well, yes and no.
they can be used but as sonic said its a big hassle for your first robot as there is more circuitry
thus there being more that can go wrong.
to run the dc motor you will need a gearbox, motor driver and motor whereas with a
servo it has all this in a small cheap package ready for you!
you see, a servo is just a dc motor with a driver circuit and a gearbox
personally i would go for a servo.