Yes, indeed, you are right. I agree with you in certain level.
I myself I do not use anymore a HW. Why? Because I am comfortable with software and I have a good knowledge level of securing my BTC wallets.
But I usually be careful to WHO am I recommending this kind of scenario.
  • some users are not so good with linux, and tech in general. So a TailsOS will not help them too much. For a 60 years old mom that barely send an email, a HW is OK and simple.
  • some users want to learn more how to use TailsOS but also could start with a HW and later move to a next level using Tails
  • some users are fucking afraid of software, so no Tails will touch them
  • some users will gladly use Tails but they still don't know how, so I wrote that guide.
  • some users are corporate users and they really need a multisig scenario, because will not be the only ones signing a tx and also are involved a good amount of BTC.
Indeed for a simple user with barely 1BTC holding, is too much a multisig and even a HW if the user is comfortable with managing well the software.
In general you are absolutely right, is enough to manage a XPUB to deposit to your cold wallet.
I always recommend to setup a cold wallet and keep it safe, not opening at all, just deposit when is needed.
As I always said: use the 3 levels stashing: HODL (vault), cache (managing funds), spending (LN wallets). Described in this specific guide - Be your own bank, but think like a bank