@jackyclever welcome to the forums! Your question is a good one as each type of technology has its pros and cons. I think personally for me, running a hypervisor provides the advantage of having an abstraction layer between your software and hardware and makes for easy backups.
For instance, if you install Proxmox on your baremetal host and then spin up an Ubuntu server as a container host (docker containers) as a VM, you have the advantage of being able to easily back up this virtual machine using Proxmox Backup Server. If you didn't have this running as a virtual machine, your options to back up your Docker containers are a bit more complex when your containers on a bare metal host.
Also, running a hypervisor allows you to setup a cluster of hypervisor hosts in the future if you want to get into high availability to keep your resources and apps running if you need to take a host down for maintenance or if one fails.
Proxmox LXC containers are also a good option for a lightweight way to run very "VM-like" containers. Again, running resources as LXC containers on Proxmox gives you an easy way to back them up using PBS.
Let me know if this explanation helps with understanding the benefits of running a hypervisor vs bare metal or a VM. If docker containers I would generally recommend running a VM. If you can run an app in an LXC container in Proxmox this is a good option too.
