You would still need to be able to displace suspended particles, bacteria, and small insects, otherwise you wouldn’t be able to teleport outside of a clean room

You could pass through anything as long as you’re willing to destroy it in the process

If you work in demolition you could take out a wall by continuously teleporting through it, if you wanted to do typical superhero stuff it would be good in a fight but nonlethal attacks aren’t really an option

Being able to teleport into a region already containing air without creating a nuclear blast requires that you can already either instantly displace the air in the target region (which would make a Very Loud Noise) or switch places with it, so there are possible interpretations of the power where teleporting into a fence would leave behind a detached section of fence or bend it out of your way

NixOS has the potential to do really well here. The Nix language has a rich enough type system to generate GUI forms for every field, and there are several projects being worked on that allow editing NixOS options from a GUI. They’re still very janky, but it’s definitely possible to get to a point where a layperson could operate them without breaking their system.