Because something that’s critical to my environment (passwords) should be hosted by a company that can provide updates, patching, and remote access more securely than I can.
Everyone thinks that they can self host critical infrastructure better than a paid service, and that may be true for a while. But life has a way of interrupting the best laid plans. Suddenly, one day, you’re several versions out of date and a different vulnerability is used to get in your network. Now you’re like that LastPass employee that was compromised via an out of date plex server.
I have the space and the know how to host my on bitwarden/vaultwarden. But I don’t. Because that’s critical infrastructure and I’ll gladly pay for someone else to host it / patch it / etc.
Power consumption.
Plus, I don’t think an enterprise grade server is designed to spin down the disks when they’re not in use.