Entry Hazards in VGC. stupid or useful? waste or win?

This question may come into many's mind that if the entry hazards are a waste of turns in pokemon VGC.they simply say this statement and leave the scene not examining or testing this topic, so it came to my mind to make a post about usefulness of these entry hazards in VGC format.
i don,t always use the best of pokemons to win as others do build their teams to counter them i also wanted to use the pokemons and moves that people least expect and ruin their strategies likewise i hav tried out entry hazards in VGC
following are the some of entry hazards ever to be found in VGC

Toxic Spikes (move) Move data

TYPE	POISON
CATEGORY	Status Status
POWER	-
ACCURACY	-
PP	20  (max. 32)
INTRODUCED	Generation 4

Effects
Toxic Spikes lays a trap of poisonous spikes around the foe, which poison Pokémon switching in to the opposing field. If used more than once, incoming Pokémon will be badly poisoned.
The spikes will not poison any raised Pokémon, nor does it affect Poison or Steel types, nor Pokémon with the abilities Immunityor Magic Guard. Raised Pokémon are any Flying types or those under the effects of Levitate, Magnet Rise or Telekinesis. Full details in glossary.
Toxic Spikes can be cleared from the field by the moves Rapid Spin (around the user) or Defog (around the target). Poison type Pokémon (that are not raised) will absorb the spikes upon switching in, removing their effect.

Spikes (move)
Move data

TYPE	GROUND
CATEGORY	Status Status
POWER	-
ACCURACY	-
PP	20  (max. 32)
INTRODUCED	Generation 2

Effects

Layers	Damage
1	1⁄8
2	1⁄6
3	1⁄4

Spikes lays a trap of spikes around the foe, which hurts Pokemon switching in to the opposing field. It can be used up to three times to inflict more damage on incoming Pokemon, equal to a fraction of the Pokemon's HP (see right).
The move will not cause damage to any raised Pokemon. Raised Pokémon are any Flying types or those under the effects of Levitate, Magnet Rise or Telekinesis. Full details in glossary.
Spikes can be cleared from the field by the moves Rapid Spin (around the user) or Defog (around the target).

Stealth Rock (move)
Move data

TYPE	ROCK
CATEGORY	Status Status
POWER	-
ACCURACY	-
PP	20  (max. 32)
INTRODUCED	Generation 4

Diamond/Pearl Platinum HeartGold/SoulSilver	TM76

Effects

Defense	Damage
1⁄4×	1⁄32 HP
1⁄2×	1⁄16 HP
1×	1⁄8 HP
2×	1⁄4 HP
4×	1⁄2 HP

Stealth Rock lays a trap of stones around the foe, which hurts Pokemon switching in to the opposing field. The rocks inflicts variable damage - a fraction of the Pokemon's maximum HP, based on its susceptibility to the Rock type, as in the table to the right.
For example, a Fighting type switching in would lose 1⁄16 their maximum HP since Rock is not very effective against it. A Fire/Flying type would lose 1⁄2 their HP since Rock is super-effective against both Fire and Flying.
Stealth Rock can be cleared from the field by the moves Rapid Spin (around the user) or Defog (around the target).

So these are some of the entry hazards and the following are my points why to use them.

.How many times hav u saw that one person who frequently switches out of the field to defend his pokemons against weaknesses

.And those turns made to stall out weather or TR with double protects or against fake out even,what do u do 

.In those turns it is the perfect timing for u 2 set up entry hazards hence not a waste of turn :)

Hope this post made u think more positively about this topic of entry hazards in VGC.