The Firefox security story has sailed compared to Chrome's, Pocket was independent but bundled in from June 2015 to February 2017, the Mr. Robot stunt, and Cliqz. Through the lens of corporate governance, three strikes and you're out till a long period passes with good governance.
Support for X search doesn't matter in the start up a browser with a single tab to do a financial transaction and then close the browser, which is how I've been using a single installation of Firefox, and will now be using Chrome. That scenario doesn't demand a good session manager, something that Firefox's transition to Quantum has ruined as I say in another comment in this topic.