Another angle: maybe the user wants to watch it in native 4K 60fps, which might require hardware that supports HDMI 2.1. I can briefly explain that. Also, check if the movie actually has scenes that use 60fps; perhaps they want smoother animation which could be simulated in 60fps.
As the news of the 4K 60fps link spread, anime fans worldwide began to buzz with excitement. The movie's director, Tatsuya Nagamine, took to social media to express his gratitude to the fans for their enthusiasm and to confirm that more high-quality versions of the movie would be made available in the future.
If you want the best possible viewing experience, you should use official platforms or physical media: