I run https://dummyimage.com, the first placeholder image service which has been online since 2007. I use a 1GB, 1vCPU instance from DreamCompute costing $6.00 per month. That's it.
The article mentions Digital Ocean provides the infrastructure so it seems the only cost is dev time. It reads almost like a promotional for DO with all of their services mentioned, which is probably why they support it to begin with.
I though about that, too, but that's not any different from using AWS specific services. I actually now realized why they use bloody annoying different names: it's free marketing when someone writes about how they implemented stuff instead of having a generic name.
Different names are alto useful for negatives. Someone writing about an issue with their CDN is far less useful than saying the issue occurs with Akamai.
In general I like to see brand signals: if someone I respect mentions that they use Cloudflare, that is useful information, even without further details.
Unsolicited mentions are usually useful, it's just sneaky paid advertising is bad.
To be fair dummyimage.com doesn't do any sort of image reading or resizing. Source doe at https://github.com/kingkool68/dummyimage