Someone who uses a dating app while on a date is showing a strong lack of respect for the person they are meeting, is incredibly self-centered or has become so accustomed to using the dating app on a daily basis that they are unable to shake the addiction.
No matter how much you were enjoying the date before she started using the dating app, her behavior is still inexcusable.
If you are worried that using your true height keeps you from showing up on most searches that women conduct on dating sites or as a potential match in her daily allotment of matches, you are misinformed.
Most women are happy with men who are taller than them.