This sounds more useful to apply to specific, small portions of the sand, rather than applying it to an entire coastline.
“We can use it to strengthen the seabed beneath sea walls, stabilize sand dunes and retain unstable soil slopes. We could also use it to strengthen protection structures, marine foundations and so many other things. There are many ways to apply this to protect coastal areas.”
What do you mean by outdated? Most captchas are there to help them train their next ML model. Relevant xkcd:
https://xkcd.com/2228/