Businesses hate recurring fees. The 2011 software was a one-time purchase. Once you bought the CD (or ISO file) and the license dongle (USB hardware key), it was yours forever. For a small business with a stable workforce, paying $50/month for cloud software feels like robbery compared to "free forever" 2011 software.
: The software includes a feature to monitor clock-ins in real-time as they happen on the device. zkteco attendance management software 2011