Yeeeessss those cute little $1-5 tiers can help pull people back in if the project is close to being backed but isn't near to the dead-line. Giving small little increments that people can go up from with a small reward can really make the difference on pushing over the edge or not.
I have personally seen people throw down for a $100-200 tier if it included something very meaningful like having a character in the game with a personality they could choose or the appearance of a character that they could influence. Which I personally think is nuts but there are totally those kind of people out there lol.