[alphazard]

B2C software increasingly needs to be at least source-available to prove security. It's hard to take a password manager or file storage product seriously if the client code isn't available for audit.

Say what you want about copyright, just revealing the source impedes your ability to commercialize it.

That means the client code can't be your secret sauce. The client code is effectively this table-stakes item that you have to release for free. The hosted server component is where you have to put your differentiators.