Originally Posted by
pdlamb
To be clear, I wasn't questioning "why a hammer?" but "why a ball peen hammer?" I've always found a handy claw hammer sufficient.
You can use whatever hammer you want, though I doubt you'll find many claw hammers in bike shops. Traditionally, claw hammers are used for hammering nails and such; ball peen hammers are traditionally used for metal work. The peen can be used to massage the dents out of fenders or steel rims and things like that.