The most significant difference is the structure.
StoryGraph is a centralised proprietary service, so there's nothing to stop it selling itself to Amazon one day (like Goodreads did, and LibraryThing is 40% owned by Amazon too).
BookWyrm is decentralised and open source, spread out on many servers, so it would be much harder for anyone to take it over. It is also part of the Fediverse so people from Mastodon etc can follow your BookWyrm account.
Edited 200d ago
@FediTips I like that explanation! I’m definitely a fan of protocols over platforms, so I’ll take a look. Thanks!