$1200 does seem crazy, but it is an ADC not just a GUI for HAProxy.
Some features include an Accelerator built upon nginx, WAF for security, GSLB and high availability.
For more information on the features - https://www.snapt.net/platforms/aria-adc/features
The following documentation should answer your question.
https://www.snapt.net/solutions/haproxy-load-balancer-gui
It is a web framework built upon HaProxy with additional features.
Snapt provides a full GUI for either cloud or on-prem.
[Edited as being promotional content]