ttv34 AV1 is a new Video Codec.
A video codec is what used to compress/ decompress digital videos which usually very large in size when they are in their RAW/ Original format from the Cameras or CGI Projects.
It will benefit users by providing a higher quality video than older/ previous Codecs if it's done in the same bitrate, or providing a similar video quality if it's done in lower bitrate compared to these older/ previous Codecs which results in a smaller video size.
In general, if it's done right, the videos will be higher in quality and smaller in size compared to older video codecs.
Best Regards.