Comment by gassi
Hosted as in self-hosted, as in run on a server with Docker/Proxmox/Unraid and accessible via a web browser, as opposed to running locally on a single device.
The solution isn't ideal for those who hoard entire romsets, but it's great for those of us who curate their collections down to a more manageable size. That can be anywhere from a couple hundred to a couple thousand games, and the metadata sources are fairly robust at that scale.
I guess the subtext was lost. I was stunned by the idea that anyone would want such a thing to be "accessible via a web browser" at all. Self-hosting is the improvement you implement over letting someone else host it, but hosting it at all was an idea that would never have crossed my mind had it not been brought up. And it creates the impression that such hosting is somehow necessary to use the software.
It's a sort of complexity that seems, to me, completely beyond what the target audience - people who collect ROMs - would be interested in. After all, they're explicitly preserving software that itself works in a far more primitive way, because they have a personal interest in software that works in primitive ways.