Having multiple E-ZPass transponders would seem to be pennywise and pound foolish.
I had Massachusetts and New York for quite a while. I live in Massachusetts but have crisscrossed back and forth between here and the New York area my whole life. One trip to the city racks up double-digit toll savings thanks to the NY transponder.
Ironically it’s the Mass one I don’t use anymore, because the savings is so little for the amount I cross through toll booths around here.
Honestly, I think there’s a level of parochialism with all the in-state discounts. I asked an official at a hearing why we were going to a two-tiered pricing system when it forced interstate travelers across small states to pick one discount or another, and he said, “I think Massachusetts drivers deserve a lower price.” I asked what he meant by that, and he said something like, “They just do.” I said that felt a little juvenile, which maybe wasn’t the best response, but it’s how I feel.