I am personally so glad Gnome does not have a system tray, on every other DE its a disgusting mess of differently scaled and styled icons.
The first versions of Gnome 3 did indeed have a system tray for backwards compatibility, and it was hidden out of the way until you needed it. Eventually it was scrapped once enough software was updated to not rely on it.
If somebody insists on having a messy UI, they can use literally any other DE available for Linux.