Can I use both the Microsoft Dynamics 365 App for Outlook and the Outlook Client at the same time?

Our office is transitioning from on premise to the cloud.  As such we now have access to the new Microsoft Dynamics 365 App for Outlook.  However since its quite a drastic change it will take time for our staff to move over.

Is there any reason we can't use both at the same time?  I have both installed on my machine and it seems fine, but I'm worried there may be issues I'm not seeing.  Like duplicated records or something.
We are using Server Side Sync for all mailboxes.

Let me know your thoughts, thanks!