Why Copilot for work data?

Imagine you work a for a company called EcoGreen. You need two things done quickly: a summary of the internal EcoGreen_Registrations.xlsx file, and a draft email to stakeholders that reflects last week's discussion in your Teams channel. A colleague suggests you just paste everything into a public AI chatbot instead of using Microsoft Copilot.

Why is Microsoft Copilot the better choice for this particular work task?