A paper-only journal would defend against the state, but not against people you live with. A digital journal can be encrypted, but an intelligence agency could potentially gain access (like, them reading your anti-government rants that may involve violence… that sort of stuff).
So… how to defend against both threats?
(Also, I just realized, paper journals cannot really be easily backed up…)
Paper jounal may not be backable up, but they are not affected by bit rot, cannot be tracked or detected by any means, they are partially or totally destroyable, and helps freeing the pressuring throughts from your head, so you would be less vulnerable under torture.
Also, one can log what you type on a device even before it is encrypted (if we assume the worst scenario). So i think keeping a paper diary, even with the comfort flaws, stay the safest option (if you hide it well and doesn’t reveal its existence).