I think it fully depends on what data Monzo are hoping to gain from this which we don’t have sight of, unfortunately.
As someone else mentioned above, if you accept the offering knowing it’s a six month contract and you’re happy with the terms then it’s all good. I don’t understand why that doesn’t sit right with people? No one is forcing anyone to sign up to something they don’t want to…
edit: the blog post does explain the data they are looking to gain from it, and doesn’t mention what will happen to the trial users if they change the offerings in the near future, so we’re all just guessing. Making Monzo: An update on Monzo Plus