Well, I'm one who plays live with BIAB on a laptop. My approach is similar to the post by Danny C.. The big advantage of the laptop to me is the ability to change keys on the spot (I have horn players and vocalists who sit-in often). I take requests, which means large files of tunes across standards, pop, country, etc... Being able to change the number of choruses to accommodate soloists is great. Also, on unfamiliar tunes, seeing the chord changes (and lyrics) scrolling is a big help. Even my horn players like to peek occasionally to assist in their improvisation.