It could be considered useful, especially if you fly around a corn field like I do. There were a couple good lines in the copy I found amusing.
"...each with a pair of ear plugs included." This is good, I like that. As you get closer, you may need them at 140dB!
"...this lost model alarm will sound when signal is lost or when invalid signals are seen." Does this include when you are flying inverted, and mean to give down elevator when it should have been up? That would be considered an invalid signal, right?
"Up to 30 hrs operation from RC battery." If anyone has lost a plane in a corn field, forrest, or similar, this shoud be just about enough time to find the darn thing.