The batteries will not in fact last as long as the gas engine will in a normal car.
Pure BS, the battery packs in the first generation Prius were good to hundreds of thousands of miles, far beyond the average ICE, and battery tech has only advanced since then.
As far as the greenness, that depends on where you are, a Prius plugin run in San Fran produces .06g/mi of NOx, well below the CARB limit for ICE vehicles and the CO2 per mile is also lower than almost every ICE vehicle. If you throw up some solar panels then the NOx per mile is nearly zero as is the CO2 (there is most likely some embedded pollution in the panels but with an eROI of months and a panel life of decades it's going to be negligible). The batteries can be almost 100% recycled, Toyota has a significant bounty on the old packs and still turns a profit on their recycling program.