If I had to complain, I'd say that usually an RTOS isn't really meant for something like button handling. You can use it and it will work, but the bread and butter workload of an RTOS is multiple simultaneous CPU/time intensive tasks that need to complete within a deadline.
The embassy scheduler here could run into a problem because long running tasks would block short lived interrupts.
I know their implementations and behaviors can be quite different, but I'd like to hear more about what makes this an apples to oranges comparison.
There's a large number of things that the cooperative scheduler can't do. Maybe you don't need those things, that's fine! Embassy really is quite nice for cooperative task scheduling. But to benchmark a context swapping RTOS which can and pays the cost for doing so, against a cooperative task queue scheduler... these are not at all the same things, and won't have the same performance characteristics in simple scenarios like the one in the blog post.