A traditional controller refers to a device used to play video games. It usually has buttons, analog sticks, and other controls that you hold and use to interact with the game. Full definition
It's pretty subtle, but the controllers also have a differing shape that can make the difference for people who prefer a more traditional controller. (nintendotoday.com)
This even goes for games with complicated mouse and keyboard inputs that weren't designed to be played with traditional controllers. (slashgear.com)
Small and short a few buttons, they still cover almost every input on traditional controller setups. (gamespot.com)