I like it! There are a lot of places to go ashore where there are waves onshore. They can beat up your beach-able watercraft unless you drag it all the way up the beach or anchor it out.
In addition if its a sailing craft, releasing the shore anchor would put you in deep enough water to put the rudder and centerboard down and allow you to hoist the sail while maintaining the bow into the wind. Anyone who has ever launched a boat off the beach with an onshore wind knows how much easier this would be if it works as advertised.
I'll be checking it out.