It's not about features, i believe i am not that advance user. It's just different from the RTOS i used to work on. Most of exist C RTOS work quite similar(FreeRTOS, Zephyr, ThreadX), the difference is mostly in API and Software support arround the core kernel.

But Embassy, with different task switching mechanism, mean i need to learn another new concept, understanding the pros/cons. That is not what i want to do when busy adapting to Rust.

In my experience unless you're really at the edge you can basically just treat it like regular threads, and you'll probably run into fewer concurrency issues than you would with threads. Probably the bigger problem is just the rough edges in async rust, though they are getting filed down over time.