For someone who has only used offline, local password vaults, what is the advantage of a cloud-based solution (for personal use, not enterprise)? I'm interested in their self hosted option, but not sure what the advantages would be over keepass and syncthing.
Convenience and portability for people who don't want to use, or aren't going to learn how to use, anything more complex than an app, browser extension, or website.
Accessing a password vault from any arbitrary internet-connected device and browser through the web is also convenient, even if to you or I that serves more as a reminder of how accessible your passwords might become to unauthorized users. Sharing credentials between Bitwarden users is also more convenient.
If you self-host, you can provide those service to friends or family members who don't have your technical aptitude. For teams and businesses, it provides an auditable service with directory integration and other optional enterprise features (SSO, fine-grained access).
All of these are possible without a SaaS, just less convenient to set up. You and I might consider setting up our own personal password management to be a fun and useful project, or at least a trivial time expense compared to the value. When something like Bitwarden provides all of those features and more for $0 to $10/year, even a small time and maintenance burden might not seem worth it to a less technically savvy user.
The big thing that got me to move off passwordstore to BW (and self-hosted vaultwarden) was sharing passwords with family. The app and browser extensions are nicer, too.
