S-57 charts are a derivative product manually authored based on hydrographic survey data. They differ from the raw data a little because they include extra metadata and hand-tweaked geometry to reflect safety issues.

To my knowledge S-100 is simply an updated “container” for ENC data and is replacing S-57. So it’s not necessarily related to this effort except that the new format may support gridded bathymetry data being encoded?

The two are mostly unrelated, IHO members are supporting seabed 2030 but the new data formats coming at the same time is more of a coincidence than anything else

Although S-101 is the updated ENC standard for S-100 the new S-102 standard will enable the visualisation of processed bathymetric data by mariners, biggest benefits will be more granular no-go areas