Passkeys (depending on implementation) are more resistant to info stealer viruses.
The private key portion can be in your OS’s credential store and can be used to sign the challenge without being revealed to the calling application.
Of course this doesn’t work if you got rooted, but a lot of viruses of this kind try to steal what they can get as a regular user, and you can get a lot, ie AWS credentials, saved browser passwords etc.
In my view it’s cheap defense in depth.
I’m reading this as a play to allow communities to have their own paid for areas and Reddit takes a cut in exchange for hosting this.
I recall a while back they were looking at a way to financially compensate major contributors and moderators, so possibly this idea is being revisited in a way.
Right now though, most people contribute to communities to share their knowledge or creativity and to connect with others- and monetisation might be there in the background but isn’t a first class feature of the platform. It makes business sense to make this play, even though it’ll make the site worse.
To conclude: Reddit becomes an only fans competitor. Calling it now.