in the sequencer the note edit page provides a piano roll display that is the easiest way to micro edit the odd missed note etc after a performance.
if you change chords by just switching relevant fingers, the whole chord is not represented at the chord change point in the piano roll screen.
say you change from g to g7 just by swapping one finger from d to f.
at the point at which you changed chords, since the g and b notes have been permanently held down, all you see in the piano roll display is a new note of f.
If you lift all fingers before changing chords, at the chord change point you will see 3 new notes of g, b and f.
this is just easier and quicker to find your place in the song when micro editing the odd missed or miss timed chord.

complex backing is variation 4 most of the time. the busier the backing, with the more tracks playing, the worse it tends to sound if you try changing chords every beat, generally speaking, as Gunnar said.

if you are changing chords just before the beat there should not really be any hesitation?