The fundamental difference between the displays is that the segmented display uses pre-screened elements which sometimes are whole characters or symbols, while the graphics display uses pixels, parens and dots to form the images that are to be displayed.
The graphics display contains a far larger number of elements, arranged in rows and columns. It uses a pre-stored font library to generate the character images that it is capable of displaying. The higher the resolution of the graphics display ( resolution meaning the number of pixels ), the better the character font it can display. For instance, a low resolution graphics display might use a 5x7 character set, as opposed to 10x12 for a high-res display. The segmented display uses seven segments to generate the numbers 0 through 9. The segmented display can only display those special characters that are designed into its display area. The graphics display, on the other hand, can portray images and special characters or symbols that are made up of its pixels.
The graphics display is only limited by its resolution and its software in terms of what it can display. The segmented display is constrained by the artwork used to generate the display. In other words, it is fixed in its capability. The graphics display can vary the point size of the characters it generates, whereas the segmented display cannot.
In devices where onscreen instructions are to be displayed only, the graphics display can be used. This feature can be extremely important in scales where varied personnel or students will be required to use the scale. The graphics display is capable of providing plots of results. In other words, the user can be given a visual presentation of the results organized as a chart. It should be obvious that the graphics display is a far more flexible display and capable of displaying information in a more understandable form. However, it should also be noted that segmented displays are much less expensive and require far less support electronics and software.
And so we come to the real world trade-off of price versus performance. Where the segmented display does the desired job, it will provide the best bang for the buck. Where a quality display is required, with visual flexibility, the graphics display is a must. If the user is uncertain of which display will best fit their application, the graphics display is the wiser choice.