Hosting at data centers is expensive, hosting at home is not expensive. You probably already pay for internet, why not use it. My home server costs me about 3

Hosting at data centers is expensive, hosting at home is not expensive. You probably already pay for internet, why not use it. My home server costs me about 3 euro per month in electricity (and it is quite beefy for a home server) and it runs many services, not just Vaultwarden. Add homeassistant for smart home, nextcloud for document cloud, jellyfin for media, immich for photo backups, etc. Maintenance using docker and compose is also trivial task. On top of that, it runs in a private network and has limited exposure to the outside world though VPN in case you need to access it away from home. Yes, hosting a single service is more expensive, but hosting a bunch is much much cheaper.