Sometimes you may want to actually use two banners — one for desktop and one for mobile — so you can control the layout with more nuance. This is a great little "protip" to allow making the text shorter on mobile, or use a smaller image (or a different/specific crop), or change the aspect ratio, etc etc.
For that, we added a setting at the bottom of the section settings for "Visibility" which allows you to "hide on desktop" or "hide on mobile."
This same hide on desktop/mobile setting is available on all of the sections, so you can use this in a lot of fun/clever ways. We recommend not going overboard with it… but it's very helpful in the right situations.
Also note we will likely add some new mobile-specific settings to various sections (like banner) in our next set of updates — for things like mobile aspect ratio and mobile background image. We're wrapping up that update now and hope to have the setting available as soon!