Safari is more energy efficient on macOS compared to other browsers.
But like it or not the (artificial) hold Safari has over the iOS/iPadOS ecosystem is the only thing stopping a complete Google hegemony over the web browser market.
Mozilla is circling the drain and the few nascent new browser projects are years away from technical maturity and may never establish any meaningful market share anyway.
The challenge for Ladybird and other independent browser projects is the enormous size and scope required of modern browsers, which is also still growing. Web browsers are now probably second only to operating systems in complexity in the personal computing space.
Plus even if they do reach technical maturity, they still have to convince people to use it. That’s not been going very well for Mozilla, and they already have a working browser.