A recessed or partially recessed shaving cabinetry is always an upgrade. The only downside is that it can be a tad harder to reach for kids. If organised before the framing is done it should add negligible cost. A wall mounted vanity is an upgrade to a floor mounted vanity. They look better and are easier to clean around and under. They do have less storage but how much would you need.

Anything that “floats” creates a feeling of more space.

My cabinet in main bath is not recessed and I peer it being closer as easier to reach higher shelves. But this is over a 550 deep bench. If narrower 450 bench you should recess. If cabinet door close to or wider than bench then recess.

When you recess the cabinet try and put PowerPoints inside for toothbrushes. It makes it look seamless.

My ensuite pre renovation had a floating vanity. The only issue was that the plumbing went down into the slab and this was visible when you were lying in bed, so no option but a floor mount for me. Due to the existing wall cavity I was only able to partially recess the mirrored cabinet but it still looks great. The PowerPoints are within the cabinet so none are visible but there is a cord hole at the cabinet base the can’t be seen. You may be restricted by existing structures if this is not a new build.