She was an accountant. I am not sure whether she was hourly or not, the issue is that accounting firms often bill clients by the hour, so internally they need correct records of the time employees are spending on jobs.

So even if she were not being paid hourly (though the court ordered repayment implies she was?), the company would have required accurate recording for billing clients.

The company also didn't just arbitrarily install the monitoring software. She was already underperforming, and on some PIP-equivalent setup when they got her consent to add monitoring software - I would guess that they were already thinking she was falsifying her time sheets at this point.