I've seen code like this for turning off asset logs in development.  If the code swallows errors and warnings then it can be difficult to start debugging.  Switching to single-threaded would increase the page load time because thumbnails and poster images aren't static.  Cleaner development logs would be nice though.

Also, the developer is complaining about every 5 seconds but in my opinion that's too long of a polling time.  That means that a job to send an e-mail to a user's inbox could take 5 seconds to start.  You can change this by setting INTERVAL in the environment but that means it's polling the db every X seconds.  Using redis through resque is a better approach.  Still, one query (that's probably cached) every second isn't too bad.