Looks like he’s storing data in the server’s file system, but I see no mention of backups. Hopefully there’s more than one copy of the data somewhere (or it’s not critical data)!
Also the problem everyone makes with backups is that they don't regularly test them. At which point storing the files on S3 would have been far easier, quicker and safer.
Plus, as mentioned, there's your backups sorted. Plus, you'll never have to worry about running out of disk space. Plus, you're taking load off your web tier, for something it really doesn't need to handle itself. Plus, massive performance boost on serving those assets over a CDN. Plus, it's really cheap, most likely a fraction of the cost of your VPS(es) or dedicated box(es).