why would a manifold be designed like this??

[ChefJ]

if you are in to power and not looks then NO dont get a log manifold unless your POWER goals are low. a tubular manifold always out performs a log manifold.

Yep. But some tubular manifolds are know to have some cracking defects.
I have an inlinepro log manifold on my s2000 and they have NEVER had an issue with it. I know of other people with the lovefab mini me manifold ( tubular style) and some have cracked. Although the tubular manifold is much more efficient.