Thanks to SeaweedFS, I've set up two replicas of the BSD Cafe's media. One is on a backup server (for disaster recovery purposes only, also containing the hourly zfs-autobackup backups), and the other is on a Raspberry Pi 4 running FreeBSD, which is one of my home backup servers - just one meter away from my desk.
I've also configured Nginx in a jail, so when I'm at home, the BSD Cafe's media is served directly from the local replica.
The performance is lightning fast.

@Nux the Mastodon media files are many - in a few days, you can go over the 200 GB.
This would require a lot of space. More, you can only have one Mastodon instance as the media files are stored locally.
With S3, I can have the media file in a different server (with large, spinning drives). This can be efficiently served by my own self hosted CDN and I can have two different Mastodon installations for the BSD Cafe (one is a backup one), as media will always be at "media.bsd.cafe".
In one word, scalability.