Having a multitude of lengths is important for vertical ice climbing because it is hard to predict how deep you will need to go to find good ice. If all your screws are 22cm's long you will not be able to get them driven all the way in, with thin ice conditions. Many climbers choose to carry the majority of their ice rack from about 16-18cm long screws allowing them the most versatility. They will also carry smaller ones for shallow placements and usually at least one long one for V-Threads.
Climbing screws have a variety of different handle styles. Some are designed for fast placement, these can have "coffee grinder" knobs on them or even bolt hangers. This allows for them to be place faster. Some designs have an additional lever where this knob attaches but this can make the screws difficult to rack on the harness.
The most basic screws have no mechanism for speedier deployment and are usually lighter and lower cost because of it.