Except it should probably be web workers that are unthrottled. However, in the current implementation Web workers do get throttled. Service workers are supposed to be for networking and offline applications, not doing cpu related things. As such, service worker lifetimes are really messy since they don't have real guarantees as to if they will randomly restart.

I am having a hard time finding where it states that web workers are treated the same as threads managing visual content. Currently timers in background threads are throttled to 1sec minimum interval however workers are not bound by this constraint. I may just be missing something, but I sure hope not. This would adversely impact many games and applications rendering many of them unusable without the web worker exclusion.

Yeah, sorry. I keep conflating service workers with the larger concept of web workers. For more intensive tasks you'd definitely use a regular dedicated worker, not a service worker.