Intresting concept. As a Security researcher, I won't paste or use a real key in an unknown site. I think you mention it at the bottom of the page.

I checked the network activities and indeed my key was sent to a backend.

I would like to see something like that written only in client mode, without sending anything to any server.

Using a generated story to assist memory is an interesting idea. (Although I guess anyone imaginative could make up their own story from a normal seed phrase, without using a generator like this)

This method could be used for any kind of password, not only cryptocurrency things.

It's a proof of concept, so it's probably not necessary to say that this needs to be available as an offline, open source program

I think there are some probable issues with decoding the story to reproduce the secret. For example if the story begins "In Florida I saw a Clever Cosmonaut run in a Garden". Then I might remember Astronaut instead of Cosmonaut, Park instead of Garden, or Smart instead of Clever

Carefully choosing the words in the wordlist would help avoid such ambiguities