TapNoiseA keyboard sound app changes the audio that accompanies a key press. A mechanical keyboard changes the physical switch, travel and feedback under your fingers. Those solve different parts of the typing experience.
What software can change
You can switch from a deep keyboard recording to a musical theme without changing hardware. You can also lower or mute playback instantly, which is useful when a shared workspace becomes quiet.
Software sound comes from your selected audio device. It therefore depends on speaker volume, headphones and the playback path. It does not make the built-in key mechanism quieter or alter how far a key travels.
What a physical keyboard changes
A physical keyboard has a fixed layout, key spacing and switch feel. Its case and desk placement influence what you hear in the room. These remain relevant even when a sound app adds a second layer of feedback.
If your main concern is comfort, layout or a key that feels wrong, try hardware in person where possible. A nicer recording will not repair a damaged switch or change your desk height.
A low-commitment comparison
First type on the keyboard you already own with sounds off. Then try the TapNoise demo and repeat the same writing task. Decide whether you wanted more pleasant audio or a different physical typing action.
TapNoise can accompany an external keyboard, so the choice is not exclusive. Keep the added sound subtle if your physical board already has a strong voice.
Sources: TapNoise sound setup, hardware-dependent features.