Yes if your only connection is wi-fi with drivers that require nonfree firmware, which is missing from the official ISO. You're supposed to discuss nonfree software in some non-official place too. That's what been stopping me as well; the system seems technically superior to Nix and not nearly as chaotic, but hardcore FOSS idealism makes it impractical sometimes.
I will admit, I was hesitant as well, but so far it's been fine. The #guix community on libera.chat is very active and has been nothing short of amazing in helping me understand the ins and outs of Guix. For any non-free software I use, #nonguix in libera.chat exists. It's less active but still pretty active (plus I pop in occasionally).
No, feel free to use the official guide, it's still very, very, very helpful. Yes, you do need to use an unofficial image, but that's just if you have hardware that requires non-free drivers (or blobbed drivers, Guix uses Linux-Libre by default).
Not the best of circumstances, I know, but it works (plus if you really wanted to, they give the derivation details in the release notes so you could just spin up a Guix VM which runs fine with the default image and generate the image yourself).