[DaikaijuSokogeki01]

Sony has every Japanese Godzilla and Mothra movie made between 1993-2016 (Shin is currently licensed under Crunchyroll). I believe the license for many of them expire at the end of this year or sometime next year, including the remaining Heisei films and a handful of the Millennium films.

The Rebirth of Mothra trilogy Blu-ray is out of print, but they are still available to watch online digitally and on Pluto TV's Godzilla channel. At least for now; RoM 1 and 2 will likely be expiring at the end of this year.

As for why Criterion picked this one: it's the only Heisei Godzilla film with a 4K disc release available in Japan. It's pretty much guaranteed that The Return of Godzilla will follow suit, likely in 2026, since it's getting a Japanese physical release next year.