Meaning, that, for example if you are practicing a 12 bar blues (jazz blues for example), you set your metronome to actually tick for the first 2 bars and then set it so that it doesn't tick at all for the rest 10 bars.
I just love exercises. Do you know how many people like similar competition/s "Dancing with the Stars", etc...
In short.
When I listen to a blues band, I listen to MUSIC, I listen to the Sound of this or that band, musicians.
Now, just imagine if suddenly, the drummer unexpectedly stops playing.
Does it sound good to you?
Once again, with the help of the metronome, you, me, any bass player internalizes that riff/groove/pattern, etc... at this or that tempo. With the help of an "objective" metronome (not my internal daydream feelings) you, me, or anybody else is playing the riff at a slower/much slower tempo and LISTENING to the nuances of your, my, or anybody else's articulation, MOOD, CHARACTER, ATTITUDE (if possible) of that measure, riff, groove, etc...
Internalizing a phrase, riff, groove, pattern, measure - means achieving the flexibility, refining your "adjust-ability" with LIVE or sequenced rhythm group, including the drummer.
From your posting, I guess you have a lot studio recording experience, and you know for sure what kind of disaster it is NOT to sync your sequencer-ed instruments, even if all those MIDI instruments have set the same - digital - tempo.
Once again.
I highly recommend to use the Metronome to INTERNALIZE just one bar/measure, just one riff at a time, and become stronger in terms of your ability to "adjust" your line (bass), to adjust your Mood, Character, even your Timbre with regards to your aural surroundings.
P.S. What's better
a. to follow an "emotion-free" and strictly-objective metronome,
or
b. some "super-charged" and emotional human tapping, counting?