It seems to me, there is no better place on earth to learn walking :)
I have only flown over the top, but my sister-in-law took her first steps on those sands. The boat, an old Dutch sailing barge, was stranded by the tide (and my father-in-law's refusal to buy an up to date chart). So they had a picnic on the sand at low water, turned round to admire the scene to seaward, and when they turned back the baby had learned to walk and was heading for Cuxhaven.
In fact, the local people need the visitors to make a living. But if you like the landscape as I do then there are always too many of them. I most like to go there in winter when you can enjoy it nearly alone if you get up early. The most interesting places are prohibited areas between end of March until end of September anway.
The decline of Baltic and Friesian beaches as holiday destinations would be an interesting project in itself. People still go there - when I lived in Berlin, every second car had a Sylt-shaped sticker on the back - but the general cultural significance of the north European beaches has been eclipsed by cheap charter flights to the Med.