Do I need an account to publish a wallpaper?
From the macOS app, no — it is paired with a hardware ID. Publishing from the website takes a free Wallper account, which you can create with Google, GitHub or an email code.
It depends on where you publish from.
From the macOS app, no account is needed. The app is already paired with a hardware identifier, so authorship is bound to the device that uploads the file — drop the files, add your author name, and submit.
From the website, publishing needs a free Wallper account. There is no hardware identifier in a browser, so the account is what ties the wallpaper to you: it credits your name on every gallery card, and it is how you ask for a wallpaper to be taken down later. You can sign in with Google, GitHub or a one-time email code, and you only need it at the moment you publish — dropping files and filling in the details works signed out.