The Wisdom 3 has newer software features (full-time access to NDL regardless of ATR, Dive Time Remaining on main screen and when in Dive Mode you can see your available dive time whether limited by ATR or NDL). Plus the Wisdom 3 has more memory to store dive profiles.
I personally would not pay the extra money for these features, but if you want to store more data on your dive computer and you like the new software upgrades, then it might be for you.
Plus it’s the latest model...and the latest model on anything is always better right? :) Just kidding.