I recently started a new SE save with this mod enabled.

It works fine when generating the surface for nauvis (the starting planet), but later it will break planet generation for all planets/moons which are not waterless. Causing them to spawn as very small single island (vanilla like).
That means there will be, with the exeption of core seams, no SE ressources avaibale to the player. just a ton of water and the tiny island in the middle.

A workaround is disabling Islands World after full planet generation of Nauvis. i suggest to add a note at the front page that explains this