Same here! - The ducks are all in favor of soil cleanups. They happily remove bus, worms, larvae, tomato plats, salad, kale, … just leaving fine crumbly pure soil behind. Fertilized too.The proper Japanese beetle is Popillia japonica, it's not exactly the same - but yes I can believe that the end result can be the same or at least similar.
Thankfully I haven't noticed the larvae damaging plants in our containers (where we can absolutely always find them at the end of the season). It could be that it's because they only appear at year's end and would do damage the next spring but they don't get the opportunity because we clean up the soil for the next generation of seasonal plants (tomatoes etc).
Last time we held a vote on this the ducks were all in favor of maintaining the annual soil cleanup.