The answer would depend in the final application and how do you like to implement it. Using MQX (or the usage of an RTOS in general) would be beneficial in terms of tasks’ handling (with mutexes or semaphores), interrupt handling, resources management as well as drivers and functions usage, which will be simpler in terms of programming and portability.
However, baremetal implementation could be simpler and lightweight, but user would require implementing the state machines required for every specific case, which could be a tedious task sometimes. So based in the application’s complexity and the preference of the developer, one option would be better than the other. The application would behave the same both ways, but the final decision would be up to the user’s taste.