Cape Westwind doesn't have a reward in the first place, putting it in the Roulette is pretty much reasonable since even if you can get an instant X tomes roulette rewards with a faster time, you'll get less compared to CM and Prae.

So technically, it'll be Cape Westwind (200 tomes) , CM / Prae (300 tomes).

It's just like how things work with low-level dungeons and getting Primals instead.
Primals - instant EXP / tomes (but less), can be compared to Cape Westwind
Dungeons - higher EXP (but takes awhile), can be compared to CM / Prae