since commercial usage is not free

Commercial usage oft the osm data is free, see the OSM license. The article even speculates that they switched from Google maps due to licenses costs.

Of course this doesn’t apply to commercial services that provide e.g. map tiles.

I assume that nothing will change for contributors, as vector tiles only replace the existing renderer.

For users this will allow better zooming and customization of the rendered map.

One alternative are monadic types like result or maybe, that can contain either a value or an error/no value.

Having the commands listed at the bottom by default is one thing i personally dislike about nano, because they take up space while being useless to someone knowing the commands (or at least knowing how to open the help in, which is what you can do in vim to achieve the cheat sheet). The alternative that vim uses, is to show the commands when starting the editor without opening a file.

I like the default OSM carto style, however as an everyday map while walking I mostly use Streetcomplete (or sometimes everydoor) as I like the ability to make edits.

Maybe use segregated=true, https://wiki.openstreetmap.org/wiki/Key:segregated

(when-not (> a b) (> b a))