There are a few reasons why you might want to swap your Civic's rigid, steel hydraulic clutch line for something else: It's difficult to get the OEM line and fitting assembly to cooperate with certain engine swaps, if you're going for that shaved-bay look then an ugly steel line running across the firewall simply won't cut it, and even if you're not going for that shaved-bay look a bit of steel braided bling is enough to spice up just about any engine bay. Although going overboard with the bling is never a good thing, the most important thing to keep in mind when working with hydraulic clutch and brake systems is the pressure involved. A typical automotive hydraulic clutch or brake line exhibits upwards of 1,500 psi internally. As the clutch or brake pedal is depressed, fluid pressurizes within the system causing the line to squirm around on its own. Imagine a garden hose that flings around by itself once the water is turned on-the principle is similar.
Flexible, steel braided lines are exactly that-flexible. As such, eliminating too much of the OEM rigid line or selecting too large of a line can result in a soggy pedal and/or poor braking or clutch engagement. An ideal clutch or braking system consists entirely of rigid line but that's simply impossible because of engine vibration and suspension travel. This is where flexible rubber or steel braided lines come into play. Use them sparingly though-like Honda did. A hydraulic clutch or brake system constructed entirely of steel braided hose isn't always the best idea.