This has been really helpful. Thank you so much for your extensive replies.

> If it's basically done automatically, why not just set it up double?

Yes, I could keep both formats around. Alternatively, I can keep just one format. Every feed reader out there supports both formats, so supporting any one of the two formats is sufficient.

Also, all my feed subscribers have already subscribed to https://susam.net/feed.xml. Even if I keep a second format around at say /feed2.xml, they likely have no reason to subscribe to it. So I decided to keep just one format around.

> Another question: Can't you just have both?

Yes, one can have both. Many blogging platforms do in fact publish both formats.

> I wonder whether you can give a little bit more on the user experience from this.

A feed subscriber is going to see the same feed entries in their feed reader, so no difference in UX.

> Is it more or less work for you to have it that way

Once it is implemented, any additional work is zero since the feeds are generated automatically.

> and how many people are really using Atom anyhow.

The users typically don't choose the format. They just use feed readers which support both format.