Because a tuner is used almost exclusively by stringed instrument players and as such is a specialty tool not used by audio engineers mixing songs and events. It would be useless in a festival setting, a corporate event setting, a theatrical setting, a conference setting, a mixing session and even a DJ session. The tuner would burn an FX slot on the console just so the stringed instrument player can have the tuner available. It is not a tool for the mixing of audio.
Now that drink dispenser, on the other hand…
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