Is there any advantage just for moving without sound?

Question

Boots of Elvenkind grant these benefits:

While you wear these boots, your steps make no sound, regardless of the surface you are moving across. You also have advantage on Dexterity (Stealth) checks that rely on moving silently.

There may be other items or features (for player or monsters), which grant silent movement. This question is about the silent movement part in general.

Is Boots of Elvenkind description mechanically equivalent to shorter: "While you wear these boots, you have advantage on Dexterity (Stealth) checks that rely on moving silently"?

More generally, is any mention of "moving silently" fluff, or do rules offer some implicit benefit for moving silently?

For example, there might be intercation with Tremorsense, maybe? Also, something explicit from a published adventure, even 3rd party, would qualify.

Answer 1

Your steps make no sound when walking

There is no division into rules and fluff text in spells or magic items in 5e, it's all rules text.

The straightforward mechanical effect is Advantage on Stealth checks. But there could be others, for example there could be a glyph of warding set to trigger when someone walks by, making a sound. The owner of such boots could want to set that condition on it.

The "also" clause makes it so that advantage on stealth checks is always guaranteed, and not dependent on DM adjudication, unlike other effects of stepping silently. (Thanks, @Pepijn).

Tremorsense

From a pure rules-as-written perspective, spells and magic items only do what they say, so strictly read, the boots do not protect you from tremorsense, as tremorsense triggers on vibrations, not on the sound the vibrations would maybe make.

A monster with tremorsense can detect and pinpoint the origin of vibrations within a specific radius, provided that the monster and the source of the vibrations are in contact with the same ground or substance. Tremorsense can't be used to detect flying or incorporeal creatures.

Again, it does not say they don't detect creatures that make no sound when moving.

Now from a physics perspective, it is impossible to not make a sound when causing vibrations, at least in the material you vibrate, because sound waves essentially are vibrations traveling through some medium. But D&D is not a physics simulation. There would be other consequences that are more obviously outside the scope here: for example, when you apply pressure on a material, then remove it, that will cause it to move, and the vibrations of that movement will create some kind of (however hard to perceive) sound. Does that mean the wearer of those boots does not cause pressure and can walk over snow, quicksand and water? Surely not.

House-ruling it

That said, we in our group house-ruled that the boots do protect from tremorsense, as it sounds so intuitive, and this has not caused issues. It has slightly improved the power of this non-attunement item, and has helped cause some cool moments, for example where a thief could walk by a corridor undetected while an earth elemental was on the other side of a door to guard it, and it also helped in a combat against Umber Hulks.

Answer 2

If you were to be walking through leaves, snow, or broken glass etc, this description suggests that you can do so silently without a bunch of crunching sounds.

A niche benefit, but it would negate any disadvantages caused by walking through these noisy materials.

Answer 3

I think this would most come into effect when you're dealing with creatures that have the Keen Senses feature, or something similar. Any kind of ability that would gain some sort of bonus from sound being made would be made irrelevant by an item with this silent effect.

Say, for example: I'm playing a character who is trying to sneak through a snowy forest for some reason. I encounter a Winter Wolf, with the trait Keen Hearing and Smell, which reads:

The wolf has advantage on Wisdom (Perception) checks that rely on hearing or smell.

If that Winter Wolf wants to detect my presence, it would likely need to make a Perception check to notice me. If I have an item or feature that says I make no sound, or that I don't have an odor, then that wolf would not gain advantage.

Basically, I don't think that this effect, or another like it, would ever offer a direct benefit to the user of the item, but I do believe it would affect NPCs interactions with the Player Character.