Not at all! The system is designed to work on personal phones, both for clients and staff, and it works on almost any version of Android and iOS on the market today. This means you don’t have to invest in any new hardware if you don’t want to.
Of course, you can also set up one or more tablets for the staff, and have the staff share them if you think that fits you better. Like most other systems on the market, they will be assigned a personal pin code to identify them by.