The power of doing any thing with quickness is always much prized by the possessor, and often without any attention to the imperfection of the performance.
If Voldemort had known about the Deathly Hallows, surely he would have sought them, done anything to possess them: three objects that made the possessor master of Death?
They won't be given access to sensitive information, so they won't have the keys to the castle – an idiom meaning to possess information or knowledge which gives the possessor access to power.
Enabling its possessors to find their way to wealth, to wind up well, to step with dignity off the stage, to die comfortably in their beds, and to get the decent monument which, in many cases, they deserve.
In comparing her recollection of Pemberley, with the minute description which Wickham could give, and in bestowing her tribute of praise on the character of its late possessor, she was delighting both him and herself.