I’m going to try to explain WAAS without any ”Geek Speak”.
This is a very simplified explanation for non-aviation professionals. WAAS :Wide Area Augmentation System is a means of enhancing conventional GPS accuracy to enable precision like approaches where no conventional ground based precession approach facilities exist. There are about 1500 of these approach procedures published with more being added daily.
What is the benefit to the aircraft owner: SAFETY and convenience. The non-procession approach has always been the most dangerous approach available. Having WAAS reduces the number of these required to be executed therefore increasing the safety of your operation. Having WAAS will allow you to land in weather conditions that would not be possible without it.
The bottom line is that we recommend updating your exiting aircraft to WAAS capabilities if it is not so equipped.