The purpose and operation of the helium valve are common points of confusion. The helium valve has nothing to do with regular swimming or diving. It has nothing to do with sealing to the limit displayed on the replica watch.
And that's because helium does NOT enter the clock, the water, no matter how deep it is held.
This device is used regularly only in projects of millions of euros of exploration of the depths or the maintenance of the transoceanic cables.
The usual dives are made up to a maximum of 40 meters. At 80 meters the air becomes toxic due to changes caused by very high pressure.
Those who do very deep research use diving bells, special suits and various other types of tools specific to deep diving. In such an environment helium is released to counteract the toxicity of air.
This valve is useful only to those who wear the watch in an atmosphere saturated with helium. Because the helium atom is the smallest atom, it will be able to penetrate the sealing systems of the replica watches under strong air pressure (not in water). If the clock is kept in the same environment saturated with helium for a long time, pressure is created inside, until it equals the pressure exerted in that atmosphere.
The problem only comes with depressurization, because helium cannot get out of the clock as quickly. Excessive pressure in the watch can cause it to explode, which is why it is necessary to use a valve that quickly equalizes the pressure. With this exception, the helium valve should never be used, as it can affect the tightness of the fake Rolex watch. This technical feature is so special that there is more than a curiosity in ordinary watches, giving the watch a special look.