It's as simple as that. Microphones aren't complicated at all.
Incorrect. Microphones are quite complex as different mics have different response patterns, output levels, behaviors in different types of environments...
There's no single mic solution that will do everything, everywhere, every time.
As for the question from mad_hatter:
What, exactly, are you expecting to get out of this mic while it's mounted on-cam? And which camera are you using? As often-discussed as it is around here, I do hope we're working under the assumption that on-cam is the last and worst place for a mic for most usable sound. What it
can be good for is nat sound for run-and-gun and documentary production. It can also be a much better quality of scratch mic for syncing to dual-system sound later.
The NTG-2 is well-known for having a weaker signal output, which means it struggles with low-cost/low-quality pre-amps. Your camera's preamps just past that 1/8" input are pretty poor. Much of this comes from the dual-power design, allowing the mic to run from an internal battery or external phantom (though the phantom-only version, the NTG-1, isn't much better). You're going to have to have a battery-powered mic if you're working with a camera that only offers 1/8" input. There are plug-in powered mics out there that are dirt cheap, but cheap is the operative word and I wouldn't recommend them. You'll need a mic that can take a battery.
As for the VideoMic Pro, as an on-cam mic it is very much an upgrade over the camera's built-in mics. If you're shooting with a DSLR it is a compact accessory that doesn't get in the way. It's perfect for on-cam nats and scratch audio. It runs on a battery, and it has a +20dB boost for the output, which can assist greatly in getting past the noise floor of the camera's cheap audio circuitry. Its shorter physical length means it only sort-of functions as a true shotgun (there isn't enough length in that interference tube to make it a true shotgun), but having used one extensively I can say that it does its job and does it well.