I'm about to test this elite status for what it's worth in 48 hours at one of their showcase resorts - ANA InterContinental Beppu. It's our second stay in 2 years there, and one of our favorite 4 resorts throughout Japan.
They upgraded us last time at least 3 room levels above our booking on platinum level - but that was during the first year of Covid, when all hotels were ghost towns here. I'm not expecting much other than a great resort, given I've added ambassador after the diamond upgrade. Finally, after 14 years of visiting these properties in various countries, I have a status worth evaluating critically.