Yes, it is possible to do it – you just need to:

1. Download pre-prepared vhdx image from MikroTik downloads site,
2. Run it for the first time on your on-prem Hyper-V (accept licence agreement and just check the basic configuration (username / password, interface(s)).
3. Convert (in Hyper-V manager) disk from VHDX to VHD and from Dynamic to Fixed size VHD (you can do it in a single operation)
4. Go to Azure portal and upload your VHD file to Blob storage
5. Prepare a disk image and vm image (that you will later deploy).
6. And finally – deploy. 🙂

What can you do with MikroTik router on Azure network? A lot of things:
1. You can use other VPN solutions to get connected to Azure network
2. You can (by using EoIP) make L2 connection to Azure network (so you can run VMs without changing IP addresses (and DNS records) which might be cool for DR solution? Unfortunately you can not do that as Azure VNet gateway captures and replies to all ARP requests so everything passes via VNet gateway (x.y.z.1) so it is not possible to extend the network as far as I was able to test.
3. You can “bring” IPv6 network (from on-prem location) to Azure
4….