Interesting shootout, a used '09 Intel Mac Mini vs. a Raspberry Pi 4 with 8GB, using Minecraft Server.
 
https://www.youtube.com/watch?v=auOXydb4LoM
 
The '09 Intel Mac Mini is the last Mac Mini with the Core Duo CPU running at 2.0GHz and external power supply with the 6.5in X 6.5in X 2in case. The '09 Mac Mini was made to break the 2GB RAM Barrier of all the Mac Minis before it (G4 Mac Minis had a 1GB RAM Limit), and is the only one of this series besides the Mac Mini Server of the same year to do so.
 
The Mac Mini was bought for $60 on ebay with everything. It had Mac OSX 10.7 Lion, but the drive was replaced with an SSD and given Debian Linux.
 
The Raspberry Pi 4 (8GB) is $75 for the board alone and to get a case with a heatsink on it, SD Card and Power supply will run you almost double the cost of the Mac Mini's $60 price. The CPU was over closes to 2.0GHz from its 1.5GHz standard speed.
 
With everything set up and running, GeekBench says:
Mac Mini: 2927
R-Pi 4:     6268
 
The R-Pi 4 is almost 3X faster than the Mac Mini.
 
But, What about Minecraft? Apparently the Mac Mini is faster, because the Wired Ethernet is faster on the Mac Mini than it is on the Raspberry Pi 4. They both say that they have 100MB/Sec network speed but Raspberry Pi seemed to lag on the network.
 
Then you have the software availability - under Mac OSX the Mac Mini wins; but under Linux, they were about the same.
 
For me, the Mac Mini wins, because of the software availability and compatibility to other Apple and PC Products. The R-Pi 4 is a great computer for its size and price but it does not have the software base the Macs and PC enjoys. The R-Pi system is great for Tinkering and to set up as a Basic Computer. Though things will be changing in the near future (like Apple moving its Macs to the Arm CPU that the R-Pi uses), there is a lot that the R-Pi and Linux can not do. And that is from the typical user wants something they can get out of the box, plug it in and use it, not needing to get parts and assemble it, burn one's OS Disk/Card/Other Media, plug it in and hope for the best. I'm a tinkerer and experimenter of computer hardware thus for me building and creating a computer system for me is not a problem.