Except for, of course, the smaller foot print, single vessel, less equipment, less cleaning. Mind you, I'm not giving up my 3-vessel, but the chorus of "for smaller batches" doesn't ring true, especially at the homebrew level. For Sierra Nevada, sure. But writing off BIAB for homebrew-sized batches...nope.
"Smaller footprint, single vessel, less equipment, " yes, except of course those are all the same thing. Less cleaning- are you throwing the bag away or do you clean it? The chorus for smaller batches is saying BIAB is the best for smaller batches. Beyond 5 gallon batches the chorus is saying BIAB starts to lose any advantages it had. It absolutely rings true.