As the other user also pointed out, it’s not Debian but rather the Gnomeproject that is by default pushing this workflow and look-and-feel style. If you try Fedora or Archlinux for instance, you will also find the same Gnome desktop (with a different wallpaper). That said, dash-to-dock is one of the most famous and installed extensions, so this means that many users prefer that workflow, but many also apparently just use gnome without a dock. When I was using Gnome, just for reference, I had dash-to-dock, but most of the times when I needed to launch an application I would just use the shortcut to open the search menu (which coming from KDE I remapped to alt + space)

Debian ships with vanilla Gnome. This means that what you’re seeing is exactly what you’re expected to see. If you want the typical “ubuntu-like” (or mac-os like) dock, you should install the dash-to-dock extension