For me, being able to go seamlessly from the loop to regular arranger play was the primary advantage of the Chord Sequencer.

I tried the big Roland Boss four independent stereo loops looper pedal earlier this year, and I couldn't QUITE get it to sync seamlessly with the G70's MIDI clock, so if you were not VERY careful, there would be a 'hiccup' at the loop boundaries, which if you were trying to overdub more arranger style tracks over one already recorded would throw the sync off.

Plus, of course, with the chord sequencer, you could change variations, fills, even complete styles, while the chord pattern was content to simply play the chords... you could play one section with Bass Inversion ON, and the next time around with normal root bass enabled.. You could get a LOT of variety out of one verse and chorus loop, and still switch out into a self-played bridge section and back, and, other than for simply playing the first verse and chorus (when you are likely singing, anyway) the rest of your time you now had TWO hands free, for playing full piano parts, two independent parts, a bass part that was independent of the chords, a sax solo with uninterrupted bender use, another keyboard's solo, another instrument entirely' solo (try playing trombone and having to play the chords on an arranger at the same time!) and so many other things...

The looper pedal is a pale shadow of what you could do with the chord sequencer....