Would you use such a client, if existed, to read and maybe post on Bitcointalk?
It is already possible to access bitcointalk via automation. There are a few people that take actions via automation.
Mostly people will write their own code to access the forum via automation. I don’t see a lot of benefit to accessing the forum via the command line or via the terminal, but I think there is a benefit for there to be a library that will allow someone to easily interact with the forum via automation.