"hidden in plain view" is the same as easy to see but no one can really see it?
Yes. Sometimes the best place to hide something is in plain sight. Especially if it's something very valuable. For example, if you had a valuable object you wanted to hide when you went away on vacation, you could hide it under your mattress (the first place someone would look), or you could put in on a bookshelf with a lot of other clutter.
Did you ever see the Audrey Hepburn/Cary Grant movie, Charade? Do you remember how the fortune was hidden in plain sight?