Why is coinjoin not a default feature of every wallet?

Raw JSON

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  "id": "4102858276938390cfc968f9fe3528e263225a982f4eaf875cac42a890bbb678",
  "pubkey": "1bc70a0148b3f316da33fe3c89f23e3e71ac4ff998027ec712b905cd24f6a411",
  "created_at": 1779691345,
  "tags": [
    [
      "client",
      "Halo"
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  ],
  "content": "Why is coinjoin not a default feature of every wallet?",
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