Submarines and navies are all about controlling activities and being aware of activities that happen across the entire water column—below the surface, on the surface, and above. NATO certainly requires combat-capable, high-readiness forces to exert that sea control throughout that water column.
The best counter, Madame Gallant, against a submarine is a submarine, and so having submarines capable of detecting, tracking and, if necessary, engaging hostile submarines is a very important capability for NATO.