Are you trying to hook Bitwig up to other realtime software with jackd? Because if not-- e.g., you're just trying to output sound from Bitwig with the lowest latency possible-- there is absolutely no point in running jack. Go straight to ALSA.
Note: I'm not familiar with Bitwig and am assuming it isn't a weirdo that somehow prevents you from setting ALSA as the backend on Linux.
The downside to "straight-to-ALSA" is that a realtime prog will gain exclusive control over the audio subsystem. So someone who wants to watch a youtube video demo on realtime prog Z and run realtime prog Z to monkey along will end up with a frozen video as it blocks (or perhaps Pulse blocks) waiting for prog Z to release the audio to it. (Or if the video started first, prog Z will (hopefully) error out trying to gain an exclusive connection to ALSA that it cannot get.)
Pulse is valuable because its default behavior solves this use case. Jack can be set up to do this, too-- I have used Qjackctl or whatever to automate this use case when setting things up. But at least last time I used Jack I had to "opt in" to this obvious setting of "pipe the running stuff to the speakers, please." E.g., I had to do business with my brain and some global mutable state. Not sure if that's changed.