Band steering is a feature that allows routers to steer client devices towards the 5GHz band if they support it. What’s important to understand is that signal strength doesn’t play a factor in whether or not the client gets steered towards the often less-crowded 5GHz band. So don’t enable band steering to improve coverage, as it will likely do the opposite. I’d only enable this setting if you have great coverage on the 5GHz band in all the areas you need. Check out this article for more information on how band steering works.