The tiny Nikki glitch is a bit more than just a visual effect. The hitbox is smaller, you can get into small crevices and under props, and also drown in very shallow water. Movement speed is the same but dashing is tied to hitbox size so it's a 1cm dash.
Weirdest part is that your own spawnable objects are also tiny and make other Nikkis tiny. Sitting on the small pumpkin locks all movement and requires teleporting out, which to a non gamer Nikki this might not seem like an obvious solution and could constitute griefing. My other props clip through the ground so I can't test if that happens with those too.
Shrinking ability fixes it in areas where you can shrink at the risk of falling off the world