You'd be delighted (or terrified) to know that I just added an old gaming computer in a 4U case to the cluster, so I can play with PCI/GPU passthrough.
The Dell is essentially the main machine that runs everything we actually use - the other hardware is either used as redundancy or for experiments (or both). I got the Pi from a work thing and this has been a fun use case. Not that I necessarily recommend it...
You'd be delighted (or terrified) to know that I just added an old gaming computer in a 4U case to the cluster, so I can play with PCI/GPU passthrough.
The Dell is essentially the main machine that runs everything we actually use - the other hardware is either used as redundancy or for experiments (or both). I got the Pi from a work thing and this has been a fun use case. Not that I necessarily recommend it...
Pis are a relatively quick and cheap (including power) way to get "another computer" that isn't a VM or otherwise dependent.
VMs can add a lot of complexity that you don't really need or want to manage.
And (perhaps unadmitted) lots of people bought Pis and then searched for use cases for them.