Yep, I would say that the upside is being able to see them in something, and to keep it and show them when they are older, and for them to have the chance to buy themselves something nice when their older, that they might not have if they didnt have the extra pennies.
Downside: is the long travelling hours on hot trains, The waiting around for the next casting to come along which is sometimes months and months. Also travelling to a casting for an hour to only be there for 2 mins and then travelling back.
But I do enjoy it and have met some lovely people through DD modelling.