To explain the issue: sea ice floats, is thin, is seasonal, and correlates to wind speeds since it is mostly just the top of the ocean freezing due to evaporation.

But sea ice does not really matter if you care about sea level. Ice cubes melting in a glass does not really impact the level of drink in your glass. What does matter is the thick glaciers over landmass, which, when they melt, add water into the ocean.