Should the new "Allow Chrome sign-in" setting be kept as on?

Chrome v70 introduces a new controversial setting, "Allow Chrome sign-in", which Chrome Portable leaves as "on".

By turning this off, you can sign in to Google sites like Gmail without signing in to Chrome

When it's on, it's possible it only works in non Incognito mode.

Also, there's another setting, "Get Google smarts in Chrome" ("Sync and personalize Chrome across your devices"), which is disabled by default, and maybe they cancel each other out anyway, but you have to know for sure.

So should you define the Portable version to turn it off by default?