It currently doesn't work with Vaultwarden. The Linux client doesn't accept custom certificates. And the Android client is paid. It is a dead-end for self-hosting.
The license is also stupidly a single sentence. Which means that use could be nuked at any minute, and any money you use to pay the developer means nothing. If they wanted to kill the project today and nuke the repo, you have no legal rights, the project dies and fuck you and your passwords. That doesn't exactly inspires confidence.