As an exercise I deliberately played as badly as possible in WGT's October best of Water Holes Sweeps CTTH and scored a massive 2640 points which currently has me in 344th place - which surprised me as I thought that 1000s of people would be playing in it...
Pardon me, but you'd have to try harder! ;)
I just played it as a FFTH (*), scored 10,949 points and ended up as #430. Thus, your observation is correct that there are only a few playing this Sweeps, probably due to the watery ball graves.
At Valhalla, scoring high was more difficult. I scored only 6,031 but became 5454th - quite a difference!
(*) Farthest From The Hole: Aim in the opposite direction and shoot with driver as far as you can ;)
Be sure to use a Starter ball!
It was quite popular here a while ago.