Another infrequent toe dipper here - say you need to send some command to a peripheral, wait for the device to acknowledge it, then send more data. The naive implementation would poll for the interrupt or just go to sleep, meaning no other user code can run in that time. A naive async implementation would spread your code all over the place - it wouldn't just be a function call with three statements. There are libraries that can give you lightweight tasks, but you might need to keep separate stacks for each of the suspended tasks, there might be other ones that don't, but require the code is written in a non trivial way. Rust with async/await on no_std can give you best of both worlds - easy to read sequential code while the best possible performance.
Errr, no. You either poll, or set up an interrupt to catch an event. The point of an interrupt is to allow other code to continue to run while waiting for a peripheral.
