Enabling this option does also block other autofill functionality in the browser, such as suggesting contact information or payment information when completing online forms. Also, there was a bug (not sure if it was ever fixed) that made enabling this option irreversible — i.e., to allow the browser to autofill payment information (for example), it was(/is?) necessary to first uninstall the Bitwarden browser extension.
Personally, I prefer to disable browser autofill functionality using the browser settings, so I do not enable the option to “Make Bitwarden your default password manager”. I have not noticed any issues with this approach.