Pro: It can really fill in on certain songs. Pro: I play acoustic and electric guitar and if my hands get tired, usually due to lack of sleep and an old neck injury that effects my hands, I can lighten up on the playing for a bit. If my voice gets tired, usually due to lack of sleep and singing too much that day, I can elaborate the song melody on guitar or double stop and chord solo type stuff for a while. Hotel California would be a good example. Pro: On danceable songs I tend to make the drums and bass a bit stronger either by mixing in the DAW or by EQ on the mixer. If the track combined with my guitar intro is similar to the original song it will help get people moving when they recognize it. Boot Scootin' Boogie and Beer For My Horses for example.
I can and do practice and perform almost all my vocal songs on acoustic guitar without "Econo Band". Many with slightly different arrangements than when I use Econo-Band. But that's because many of the tracks I make include a solo/interlude section and often the solo I have worked out sounds thin without the rhythm section going.

Con: Econo Band is not going to adjust for you if you lose timing or if you lose your place during the song. This can induce Turret Syndrome which is not good for public image. So, practice with the track extensively and you might even want to be somewhat consistent in your song arrangements so they are easier to follow. Con: Getting your tracks to be a consistent volume is another. I run the mixer from the stage and connect my Econo Band mp3 player to a stereo volume pedal to help counter this. I don't know the ohms of the pots in the pedal but I know that does matter. Mine just seems to work. It's a cheapie made by Rogue. The volume pedal also allows me to fade out a song if I don't feel it's going well or if I accidentally repeat the same song.
I also use a bass kick drum and play a tambourine with one foot. Only one foot at a time. I don't use both feet and play both at the same time. I do this with or without the Econo Band. Usually on the 1. On the 1 and 3. Or on the 2 and 4. Tapping the tambourine during the chorus for example. It help add some dynamics to the song. Con: It doesn't really allow for other musicians to join in with you on the fly unless it's a standard blues tune and they play a solo type instrument. But it pretty much eliminates a bass player, for example, if one wanted to join you. Con; If most of your songs are performed with tracks and you know some songs that you don't have tracks for are you eliminating some good songs because you think they will now be out of place without a backing track? Or, can you feel confident playing those songs without backing tracks and not lose the energy of the audience due to the simple change in dynamics from full band sound to singer/songwriter sound? If you do this be careful how you arrange your set. You might not want to go back and forth too many times from tracks to no tracks.

So there's a little on some of the pro's and con's I've experienced and how I've overcome some of the cons.

Does the noise in your head bother me ?