SMB only (There is/was a way to make Windows do NFS, but it sucked.)

License cost. The desktop versions of windows (used to?) have a limit on concurrent SMB sessions in order to force users to buy the server version and pay for CALs. No idea how any of that works now.

NTFS is kind of a shitty filesystem.

Limited (native) backup options. No tape support, for example.

Management effectively requires GUI access.

No native way to mirror the OS drive in software. You need either a hardware RAID card (LSI, etc.) or that stupid Intel BIOS RAID thing.

These may or may not be issues for OP, but they are issues for many.

You will likely hit the RAM limit (64GB) before you run out of processing power for most “normal” VM use cases. You should easily be able to run a dozen or so VMs.