This question is about Cycling
Cyclists eat rice cakes while biking because they are easy to digest, non-perishable, easily portable, and rich in carbohydrate - the preferred fuel of working muscles during long cycling sessions. They can also be handy post-ride when repleting carbohydrate stores is critical for recovery.
While rice cakes can be handy on the bike, they are not considered a nutrient-dense food. Rice cakes lack health-promoting nutrients including fiber and antioxidants and may contain excess sodium [ 1
Mir, S. A., Bosco, S. J., Shah, M. A., & Mir, M. M. (2016). Effect of puffing on physical and antioxidant properties of brown rice. Food chemistry, 191, 139–146. https://doi.org/10.1016/j.foodchem.2014.11.025