I haven't used ROOT so I don't know how well it would work to write bindings for it in Haskell; it can be hard to provide a good interface to an implementation that was designed for a totally different style of use. Possible, just difficult.
EDIT: there's one at https://hackage.haskell.org/package/HROOT
In other words, why do you think it’s not a good fit?
Using something like Haskell for ROOT is ridiculous for a lot of obvious reasons. A simple and dismissive "no" invites the cautious reader to discover them on their own rather than waste engaging in a protracted debate. Maybe it's better to reject the idea out of hand and spend our time elsewhere.
You’re free to not do any of that, of course, but be prepared to defend the fact that you’d prefer not engaging in discussion and instead just shallowly dismiss something.
It's much more likely the physics community would adopt Julia, or maybe Rust, and even that has been pretty slow.
(nothing I said above should be construed as taking a position about the suitability of any specific language or lack thereof for doing scientific computing. I have opinions, but I am attempting to explain the reason factually with a minimum of bias)
When the cost of complexity of interacting with an API is paid by the LLM, optimizing this particular part of software design (also one of the hardest to get right) will be less fashionable.
TTree is succeeded by RNTuple, which is basically CERN's take on Apache Arrow, they're incredibly similar
I left about 5 years ago, and ROOT was in a process of change. They already ripped out the old CINT interpreter and moved to a clang-based codebase, and now you can run your analyses in Jupyter as far as I know (in C++ or Python). I heard the code quality has improved a lot, too.