Panasonic IPPTs (IP proprietary telephones) do more than conventional VoIP telephones. They perform better in call centers and anywhere that people need to answer incoming calls for their group. They also perform better as shared phones, where two or more people use the same phone but have individual extension numbers (e.g. shift or part-time workers). The user interface is friendly and intuitive, with no need for confusing "contextual menus" that make competing brands of VoIP telephones annoying to use.
The printed-label IPPTs look and work exactly like the KX-DT digital telephones, with 24 programmable buttons. This is a substantial benefit in "mixed" or "hybrid" installations, where some phones are digital and some are IP, such as to save cost on new wiring.
The self-labeling IPPTs have their programmable buttons labeled on an additional display, instead of with printed labels. This is a substantial benefit in all-VoIP installations (the majority of new installations). There's no need to re-issue new printed labels when changes are made (the displays are changed when the buttons are changed). Users who move between desks can often move their own phones, saving service charges.