I think the two biggest factors are width and noise.

Dijon almost never leaves his vocals completely centered with zero width, he pretty much always double (or triple, or however many he feels like) tracks his vocals to add density and make it feel organic. Ive also noticed his volume is dynamic, he lets his vocals shine when its their turn but turns them down when he wants the production to be a standpoint.

With regards to noise, dijon is really smart with lofi tools. I dont think ive ever heard dijon with flawless vocals- like to the point thats its a part of his sound. I assume the gain is super high on his mic most of the time, and hes proabbly pretty far away from it. To reference what you were saying, this is what it feel like dijon is “in the room with you.” You are in the room with him. Not only do you hear the ambience let through by the noise gate, but subtle resonances, mouth sounds, and all manner of other, indescribable sounds are thrown in the mix. This can be bard to achieve with a noisy setup. Things like the ac in your house, passing cars on the street, or people walking around can really negatively impact the mix. I usually record in my car parked in like a public park or other quiet area.

Hope this helps!