The Props are Metagame Information

D&D is an incomplete-information-game. Players only have a bit of information, usually about themselves, their capacities in-game. But a lot of what they do or don't do is based on inference from the structure of the game. 

D&D metagame information examples: 

• There is limited time to play in this session, and it's likely that someone will want to take some action that has narrative consequence;
• The map has four named locations, so each of these is a worthwhile destination–a place where something will happen; 
• The referee painted a model of a giant scorpion–and it's right there on the table–so there is the strong potential of a giant scorpion being present in this game, this session. 

Abundance and scarcity is information, and a referee can use this information to establish the tone of a game and create surprise. When players see the same old miniature Chaos Warriors sitting in front of your mug of gin it tells them something about the world: whatever those things stand in for is on the map. To this, adding just the occasional new element can actually evoke a sense of fearful wonder even in the most jaded of Adventurers, and make them really unsure, in game-terms, of what they're up against. Changing the set dressing is efficient and you don't need to say anything.

All this is to say: props and game pieces don't need to be used to be useful. Your game will be different for their presence. 

Limited variables are the quickest way to establish whatever your normal is. And it's only when you've got a normal that shit can get weird.