That project is a great step forward to cutting the dependency on using fossil fuels as "reserve energy" for when demand exceeds what the grid of renewables can create. There are however some details to that design. The linked project storage is 75% capacity for 4 hours, and it usage is for solar and storage which has a daily charge and discharge cycle (customers will be daily buying the stored energy and thus repaying the storage investment on a predictable and daily basis).

In order for Germany to abandon the dependency of using fossil fuels for reserve energy the storage would need to have the capacity of the full grid, it would need to be able to last weeks, and the capacity of wind would need to be able to fill both the storage and grid demands at the same time.

If and people are willing to invest into wind power plants which overcapacity won't have a buyer but will simply be there in case the batteries need to be recharged, and people also investments into batteries which won't be discharged and generating revenue unless the weather makes wind production go below demand, then there exist a chance we can replace the fossil fueled based reserve energy with wind + storage.

Currently there does not seem to exist a single wind + storage project out there. I suspect the above economics is the reason for that.