Differently presented in the manga from the LN though. In the LN, there is no cove - just a sheer cliff face, and Yuna creates multiple bear golems to surround the Kraken in a semicircular formation. In that sense, it makes more sense to leave at least some of them as a reminder, where in this case, you would be blocking the entrance to a potentially useful cove...
Man everytime she builds one of those gates i can't help but be reminded of those hero relics ud see in other mangas, I mean just picture the far far future when the find this stuff.