Working in Google files speeds up collaborations, but IT departments need to be keenly aware of any Microsoft office/file usage needs across your organization. Why? Because unbeknownst to you, there could be segments in the organization who need them for reasons outside of their or your control, perhaps because of file format requirements from outside agencies, working with outside partners, legacy files, etc.
When this needs arises, it is advisable to deeply understand the why and the constraints. If it's just a preference, then sure, you can encourage Google tool use, but beyond that, if there is a specific non-negotiable need (as mentioned above), they might be experiencing file corruption issues when they use Google Drive's native compatibility feature that translates Microsoft files into the Google format. If this will inevitably cause dissatisfaction with the IT tools and IT's support, as well as #ITcost for your company in storage. Because, likely, people will start uploading and downloading Microsoft files, perhaps even emailing them instead of sharing, creating multiples of the same, resulting in increased storage costs and slowdown in productivity due to version control. And when the dissatisfied voices get louder about Google tools, it's hard to mitigate the damage.
So why not provide solutions instead? Consultations can ensure that those who need it, have Microsoft Office, and can use it in conjunction with Google Drive: raise awareness about how to store files in Google Drive, and share best practices for when to use Google Drive via Chrome vs. Google Drive for Desktop for natively editing Microsoft files.
Be or provide consultative guidance to your users so they can comply with IT's requirements and still get their work done.