Various Mil air frequencies and some 400MHz range are blocked on the Japanese version. Your BC75XLT does not RX Mil air now, so you may not be bothered by not having that on the R30. Also, any firmware updates need to be the one intended for that version. For shortwave, AM & FM broadcast, civilian air and up to around 253 MHz you’re good until the gaps hit.
As tempted as I was to purchase radio stuff in Japan I avoided it, due to the coverage and price concern. I only purchased a tiny broadcast radio so I could listen to the Sumo matches and some music. Even camera lenses were several hundred dollars less in the U.S. It took all of my willpower to not purchase a new lens once, but I was leaving and coming back shortly.