Before the transactional changes, this was originally there to avoid having many workers all start processing at the same time (which happens in two scenarios - when a new worker starts or when you've queued a set of short running jobs) - it helped avoid stuck jobs.
But, with the more recent move to transactional queuing it's likely not necessary - though we've never tested w/o it (we have ~4 months in production with no stuck jobs at all - after 10s of millions of jobs - so it's pretty battle hardened as it is).

Note that the setting with 'delay' (the 30s random interval) is really important still.  It protects against an error storm when redis (or the connection to it) goes down.