Actually, the more you do it, the more enjoyable (and interesting) it becomes. I'm not too keen on knocking in bats with scuff sheets on though - I much prefer seeing all the dents and grains opening up. Call it the "fruits of my labour"!
Agree on it being interesting, different manufacturers, types/qualities of wood, even 2 bats that are the same make and model will all have their own quirks and will need something different each time during the knocking in process.
Having a bowling machine certainly helps make it less draining, working on the face as well as getting myself into nick (against gentle half volleys) is a good way to pass the time. I don't envy you sitting in the corner at IJC whacking away with a mallet
Scuff sheets are a nightmare, almost impossible to round the edges via any sort of shortcut method (rolling pin, sink rim etc) and they bubble up horribly round the edges when i use a mallet.