IMHO, no.
Let me explain: crouching allow you to reduce your exposed surface, making you a smaller target.
It could be useful, but crouching has a downside: it impedes your mobility by reducing your speed.
Since most of the weapons allow somebody to one-shot or two-shot you, good speed and unpredictable movements are your greatest way to survive.
That's why most of the time, crouching is the easiest way to die.
gaming.stackexchange.com/users/7098/Lysarion
yes it is.
Crouching reduces the amount of surface exposed to a possible enemy hit, while it is pretty much useless to use while walking it is usually used in midair, especially if you're moving in an area where you are an easy target.
It is not a big deal tho, sometime people may miss you because you crouched, but good players know how to shoot
gaming.stackexchange.com/users/19797/Dix
Crouching in an unexpected moment can save your life.
One example is a shotgun infight - a crouch in the right second can negate a otherwise full hit.
Same goes for rail gun fights at medium distance.
And yes, for gauntlet as well.
gaming.stackexchange.com/users/20041/Philipp
When you crouch you move silently, I think most players crouch because they forget you can walk silently without crouching (I have it bound to shift).
Either that or they are just doing it because they can.
gaming.stackexchange.com/users/11888/Flyphe
In some situations, I find it to be very useful :) In some maps, e.g. in Asylum (screenshot) , you can crouch and shoot through the gaps between a wall and the floor :) You'll have to aim quite precisely, but it can be a very effective technique.
Your target will most likely not expect it / won't immediately realize where the shots are fired from, so there's more chance of dealing fatal damage.
At least, that's what it does for me.
(oh noes, blew my cover)
I don't think it's of much use to have both players crouching, but it can be effective (and funny, I admit) to 'sneak up' to a target, jump up and surprise the other player or to deal blows with the gauntlet from your crouching position.
As a bit of a noob player, my first reaction would be to fire straight in front, which is a waste of ammo and by the time I've realized someone's kicking me from down below, I'm already dead.
Woops.
gaming.stackexchange.com/users/65636/Ann DH
Crouching is good, for example, when sitting with gauntlet close to a teleport exit.
One common technique is to make tens of frags when playing FFA on Asylum by taking Quad Damage and meeting all players coming from teleport with a gauntlet.
For most of them this is an instant kill (150 damage in one hit) and crouching makes you a bit less visible from other parts of the map.
gaming.stackexchange.com/users/73677/Display Name
In Quake Live I see users crouching when using gaunt or shotgun. Is there any advantage to crouching? Or are these players doing it for no reason?
Is crouching in Quake Live useful?
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<quake-live>
gaming.stackexchange.com/questions/50442
gaming.stackexchange.com/users/19347/m3tron0me
Crouching reduces your speed however it does reduce the surface exposed to an enemy hit. While there is not any standard use for crouch, that might help a player accordingly, it is commonly applied as an action.
It is implied that crouching is not usefull at all or can handicap your gameplay. Most people find different uses for crouch, while playing.