Why ?
I always have a lens on my bodies. So what is so cool about a mediocre lens cap ?
Body cap + Super compact 15mm F8 lens all for £40. How cool do you want it?
It makes most MFT cameras coat-pocketable and costs close to nothing. Daylight image quality on a camera like the OM-D will be better than any P&S in terms of sensor attributes (DR, tonal and color range etc), and optically this combination will be just fine for non pixel peepers. Sounds like an interesting combination.
It would have been much more interesting though as an ultra-wide or a fisheye. These are usually quite expensive, but should still be cheap as f/8.0 lenses.
Agreed with Klaus. It's too mediocre to be interesting, regardless of the price. The killing part for me is the fixed aperture. If at least it was f/5.6, but the aperture is fixed to f/8 which is way to much for MFT and useless in anything but bright light.
Finally, one can get the excellent Panasonic 14mm f/2.5 which offers roughly the same focal length and it can be had for 175 USD on ebay (just got one)! In comparison the body cap lens is quite a crappy value.