They were considerably more than that. They had thoughts and feelings. They had minds of their own. They had souls. Wanda may have used magic to give them life, but even the Scarlet Witch can't create a human soul.
Billy and Tommy were twins supposedly born to Scarlet Witch and Vision; in reality, they were magic constructs, created by Wanda's hex powers. It was revealed that she used slivers of Mephisto's life essence to give her children souls. Tommy and Billy were eventually reabsorbed by Mephisto and ceased to exist.
Years later, two young men appeared - Billy Kaplan and his twin Tommy Shepherd - who are the reincarnations of Billy and Tommy Maximoff.
Powers and Abilities
Pandemonium said that Tommy and Billy possess mutant powers.