It adds depth and ambiance to your music. Most people like to add at least some reverb to the whole mix, to make it sound more full. As long as your -10 equipment can handle the higher input level you'll be fine. Prevent overloading it by keeping its input-level set low. Balanced lines offer excellent immunity from hum and noise pickup.
Any noise pick up cancels out neatly.
These are line levels. Its called the X-Y setup, or something like that. Sure, it's real simple. It takes two directional mic's and you want them to be as closely matched as possible. By directional, I mean either cardioid or hypercardioid, pickup patterns.