Whether something is "recommended" is going to be very subjective. Your recruiting department, for example, appears to recommend it but I assume that doesn't answer your question.
If you're doing secret projects for the NSA or knowing about your secret projects would create problems in the marketplace by allowing information to leak about new products, that's obviously a concern. You probably wouldn't want a random candidate coming to a stand-up discussing the development of the iPhone before its release. On the other hand, the secret projects most companies are working on aren't particularly closely guarded secrets that would move the market-- not too many people are going to care too much about the secret "find the new potato chip flavor for the fall" project is coming.
As your recruiting department has found, there are definitely potential benefits. It's one thing to tell a candidate in an interview that the team follows an agile methodology, that it respects work-life balance, or that it's a fun place to work. It's a whole other thing to show them those things at an actual stand-up. You're likely to be able to get much better talent if you can get them excited about the job.