One book vs. inserts (such as Traveler's Notebooks)

I've been using a hard bound book for my bujo for years now and recently started carrying around a passport sized Traveler's Notebook for when I'm out (bujo stays at home, only because I feel it's unnecessary and unwieldly outside most of the time).

I find myself thinking about using this insert formula for my bigger bujo (I like A6), but I'm not sure if it's because I think it might work out for me or if it's because I'm just grooving on organizational systems because I'm not a good manager of me.

So I'd like to ask what do you appreciate about your system, whether it's an all in one book or an insert system (like Traveler's Notebook or Paper Republic). Also, if you don't mind sharing whether you take your bujo with you everywhere, even on mundane tasks, or only when you think you'll need it.

Thanks!