As Thomas said, it shows places based on the current extent of your map. If you want places in the Netherlands, you should zoom in to the Netherlands. If you put the Netherlands as your default search place in your account settings, you will always start zoomed in to the Netherlands.
I think “useful” is fairly subjective, and iNat intentionally doesn’t put a lot of restrictions on what kinds of places can be added by members of the community. If you have concrete suggestions for how you think places of interest can be improved (e.g. it should only include places that are fully contained within the current map bounds), you can add to the Explore brainstorm here.