Paul you can do so much more "mutitracking" & recoprding your vocal harmonies in studio within the "song mix" then singing them live in real time for "certain song arrangements" leaving you to concentrate on lead vocals and playing keys with your BT "band members"

I have 4 hours worth of pre-recorded backing tracks and many feature harmony that I recorded in real time with a harmonizer, and this allows me to use different approaches to playing these crowd-pleaser songs. I can use guitar, sax, flute, stand out front, play 2 handed piano ... whatever the spirit moves me to do ... Still, I need the option of adding my trademark "Four Freshman-esq" sound on the fly to add some flavor to my shows. I do not think my use of harmony is gimmickry at all, in fact I think it defines my sound, and as much as I am confident in my vocals, I still love the package of me ... with me, me, me and me accompanying ... ME!