Specifically with Poor Things, Disney has not been releasing 4K UHD discs for recent productions from their Searchlight imprint. They haven’t double dipped. They just don’t do 4K UHD discs for those titles.
Is it possible they’ll double dip down the line? Sure, anything’s possible. Is it...
To be clear, it is available for digital purchase in 4K UHD resolution. But, as is standard practice for digital coupons provided for physical media from Movies Anywhere participants, the digital code provided with the disc is provided at the same resolution as the included disc.