Not so, I do as J F does. If I'm stood in a queue for a till, I'll sort out my change to use as many coins as possible and also use them up at self service tills (I do like her "scan & swear" description, so very apt). I also use 1p, 2p and 5p coins in vending machines.
If you dump the 1p coins, then it'll be 2p, then 5p coins and businesses won't round down, they always round up.
You can always use the coin changing machines found in many supermarkets, although they do deduct a percentage for using them. Alternatively, drop your "shrapnel" in a charity box.