it doesn't work with games that update constantly.
True, but unrelated to t++.
Any game that update will render some, or all files obsolete. Translation naturally follows suit.
On the contrary, T++ would stand as an exception, as it converts stricly 'string by string'.
I think there's a way to inject an old tranlation (the how is kinda fuzzy to me as of yet) but you can certainly brute-copy/paste your old columns into a new project. Stuff will be left out, but not all will be lost.
RPGMV and its convenient json files would add to the exceptions. After a small update, you could compare the files between version, say with notepad++ compare module, mark the differences, and review then through T++. Or edit the files directly, of course (any change to the js scripts often should be redone from scratch, though).
This is still a lot of work, nigh impossible for older engines. Usually it's best not to rush and wait for the updates to stop... Assuming they do and the game doesn't have a modding community still active 5 years later (Rhapsodia...

).