I checked out Sakura Mobile today and they have improved their "Long Termin (e)SIM" offering in two significant points:
- you can now signup for this contract even on a short term visa, but you need to pick up the sim card (or QR code for eSim) in person either in their Shinjuku office or at the airport (Narita/Haneda/Kansai)
- they have lowered the fee to suspend the contract from 1100 Yen/month to 220 Yen/month

Other aspects:
Downsides:
- you need to sign up for at least 3 months (see pick up link above)
- high activation fee 5,500 Yen
- compared to international eSims high monthly price (3,278 JPY/mo for 5GB, 4,378 JPY/mo for 25GB)
- you pay per calendar month, e.g. 20. Oct - 10. Nov = 2 months

Positive:
- SMS/Voice roaming outside Japan is possible, neither Mobal nor Hanacell support that. They state that voice isn't supported on suspended contract, so SMS probably isn't either. You can only suspend & reactivate starting at the next month, not immediately.
- MNP is possible, so you can port your contract to a different company and they can reissue your sim card (not possible with Hanacell)
- Tethering is possible (doesn't work with Hanacell, not sure about Mobal)
- Unused data carries over to next month