They don't have the same limitations that you have on a console. Steam input allows you to bind any button to the following things:

• keyboard buttons
• mouse buttons
• controller buttons
• system actions (volume, power, etc.)
• controller actions (controller slot toggle, controller power, action layers)
• steam actions

And probably one of my favorite but underutilized:

• Games can also provide custom actions that show up in the button bind menu, and they can be basic things like "jump" or really bizarre things like "make character think." Games can have built-in action layers as well, so you can bind buttons multiple times for different layers such as "in combat", "in a menu", "dialog", etc. which means you can have contextual actions be different to match your comfort (think PlayStation × vs o regional differences in-menu and in-game where o is confirm in menus but × is the main action button in combat).