Basically my only comment would be to use any platform (virtual or physical) that fits our system requirements. There is no difference in what to use for Veeam Monitor, both configurations are supported.
Based on my experience the majority of our customers are deploying Monitor server in a virtual machine and they see no issues with that. By the way, my own lab is also running in the VM too.
And just on a side note, if your virtual environment is relatively large, then I would strongly recommend using remote SQL Server for storing Veeam Monitor database.