1. In chrome, you don't need to manually add anything; you don't need to assign a keyword that you have to memorize. All the websites that you frequent that support OpenSearch will be automatically added by Chrome and you use their domain as keyword. I can now type en + tab to search on Wikipedia, as well as hundreds of other websites (no exaggeration) without manually configuring anything.

And on top of that, if you want to manually add anything (maybe it doesn't have OpenSearch), or assign a different keyword like Fx, you can still do that in chrome://settings/searchEngines, like Firefox.

2. Chrome's quick search supports auto completion. Firefox's doesn't.

It was not a big problem for me before the change of the Search Bar in Fx, since you can very easily add OpenSearch engines there and get auto completion too. But the new "One Click" makes it very hard to use (particularly the auto completion part). Now I have straight up given up search bar.