Well, for those of us who don't have quick-release, the spanner is pretty useful for the odd occasion I've forgotten to re-tighten my back wheel properly! Or there's some brake adjustments that just have to be made, or the gear cable slips...

Spot the person with the old bike who doesn't have allen key throughout!

Richard, you probably won't need one if you've got a lovely new bike.

Ellie - not jealous at all...