Nuclear war is bad in general, m’kay? Mass slaughter with a nuclear torpedo is not morally inferior to mass slaughter with an ICBM
Doomsday engineering is often stranger than any science fiction. The things they built back in the cold war were weird. While the US never admitted to building any 100 megaton land torpedoes (probably because Russia doesn’t have as many important coastal cities as the US does), we certainly worked on some completely bonkers nuclear objects.
Source: Putin’s nuclear torpedo and Project Pluto | Locklin on science