Do you need to put aside money for insurance, ongoing repairs/maintenance, restocking physical goods, vandalism/loss of the machine for apps?
I think vending machines are not really a realiable income when looking at the costs that might occur.
So, I'd take any 4-figure app over any amount of vending machines.
(How much does the average mobile app make? Does that low 4-figure amount (edit-to-add: per year) mean that app development is a dead end?)