It’s possible to ‘walk’ one or two steps in many games with Geometry 3D support. Not really roomscale, but there is positional tracking in many G3D games that allows for a little bit of movement.
Some games with positional Direct VR support (direct manipulation of a game’s camera, e.g. Bioshock series, Half-Life 2, Left for Dead 2, Portal 1+2, Fallout 4) also allow a bit more than that, which could be called ‘basic roomscale’.
Yes something I’m just learning now. In most games (that I’ve played anyway) your head essentially becomes your cursor. Meaning that you if you turn your head to the right while walking your character will turn in that direction as opposed to still going in the direction you were but just looking right as you do it