few issues with what most of wrote above
First thing - could anyone post a link or a reference to the fact that the USB cover is needed for water resistance? I do recall where I saw it but I do recall seeing a mention that this cover is needed for dust resistance (since such particles could cause damage when connecting a cable) but not water resistance - see lack of a flap on the sound jack on top.
Second thing - on German ebay the covers are between 6.5 and 10 euros a piece - so one dollar a piece is really a bargain
Maybe prices will change but it may just be typical European overpricing, oh well...