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.

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