progressive glasses offer a progressive power transition so that the wearer can achieve close vision, distance vision as well as intermediate vision through different parts of the lens. Then people can get used to them easily. What's more, progressive glasses have no visible line, so people can't tell them from regular single vision lenses. Therefore, progressive lens offers a natural look.
Traditional bifocals and trifocals may bring "image jump" since they have sharply defined boundaries between different parts of the lenses. In contrast, progressive lenses offer a smooth and seamless power transition, so that images at varying distances are also smooth and comfortable.