First of all, is this material strong enough? A Micromouse can collide with a wall under its own propulsion. You can assume a wall in a maze is solid. The next question is how fast is your robot traveling when it collides with a wall. In addition, you need to make sure the material you use is not excessively flexible because flexible materials promote vibration.
Secondly, is this material easy to work with? Although the Micromouse class has ``traditionally'' arranged with the Mechanical Engineering Department's machine shop, the general consensus is that it is quite difficult even to attend the mandatory orientation classes. It is better if you can work on the chassis at your own time and at a place that you choose.
Last but not least, is this material easy to acquire? Be warned that you may need to make several chasses before you are satisfied with one. Expensive or difficult-to-get material makes it difficult to prototype and refine the chassis.