Doing 1/2 its job?

Being now the proud possessor of a flaming fleet of Fly Swats I'm reducing the outnumbering odds I was fighting.
GRUMBLE ALERT!
What is this modern fixation for selling things in multiples?  Want a battery?  Forced to buy 2.  Need three?  Forced to buy four.  Will you EVER find the odd one when it's needed?  Only a family of dedicated Fiendish Fly Floggers really needs/wants three Fly-Swats?  Flies, being somewhat akin to the $6,000,000 man are almost indestructible; having smitten this little villain I observed it still twitching.  Being aware that a totally dead fly will not active a Venus fly-Trap I thought I'd see if the same holds true for a Sundew?

Extra - whilst on my customary Prowl and point I spotted this Cushat on the fence twixt me and next door.  As their usual M. O. is to dematerialise from the fence at the far end of the garden as I round the corner into sight (Can I really be THAT hideous s sight?); the fact that this one let me walk slowly past it en route to base was too good to miss I thought?