I don’t mean a plane of 2 tris, but a larger water plane instance than you could get by with if you had to handle LODs yourself. You shouldn’t be so quick to assume what others know especially since I’m one of the few who actually agrees that tesselation is past it’s prime.
Edit: or more accurately it never really had a prime…
One fairly recent example (not UE, but regardless) is Far Cry 5, which rejected landscape tesselation due to it’s cost but did use water tesselation. Many shipped games use it for water even if they don’t elsewhere.