Why is anything you can touch and pick up not a good definition of matter?

The ability to touch is a both a good and weak example of matter. For example gasses may only be felt through air pressure and current. They may not be 'touchable' in the conventional sense. Under this reasoning just because it cannot be touched does not preclude its existence. There are also other forms that include dark matter which is not visible to human eye, as other examples to limitations of touch detection and identification.