Google tells me there are about 70 instances of Hope this is helpful on English Language Learners.
I don't like to come across as a grumpy ole git, but it seems to me this level of "chattiness" isn't really appropriate in ELL Answers. To me it's a bit like Thanks! [in advance] added to Question text (which I habitually edit out).
It's a straightforward question, so if you agree with me Upvote this post. If you don't, please Downvote it. If I'm massively outnumbered, I'll shut up.
EDIT: I've only just realised from comments that some people assume I'm proposing that all "chatty" text should be unilaterally edited out of all Questions and Answers. I do usually remove Thanks [in advance] from Questions if I'm editing for some other reason anyway, but probably not if OP is an "established" user (in which case I assume they're aware of "SE site norms", and don't need my "guidance").
Note: Should 'Hi', 'thanks,' taglines, and salutations be removed from posts? is the ninth most popular question ever on SE.meta, and the top answer there has by far the most upvotes I've ever seen on SE. The top three answers there all say Yes, delete on sight!, but my vote went to the more "moderate" fourth answer saying only if other reasons justify an edit.
I'm not trying to define (definitely not enforce) any "rules" here. It's just a straw poll to see how ELL users in particular feel about the "avoid chattiness" principle endorsed by SE users in general.