You can certainly do whatever seems simplest and cheapest, now. But, look ahead a few years and consider how difficult it will be to expand this 'hardwired' layout. Even something as simple as moving a plug to a different jack on the same router may be impossible without a Cat 5 coupler.
It may be neat now, but, any moves, adds or changes will get real ugly real fast. Perhaps this client will never expand their network beyond this point, but, what if they do? Will you then feel like punching down the old horizontal wire (presuming there's still room in the closet for a punchdown block)?