Administrative overhead and float are 2 off the top of my head.
Automation makes the first one easier, but unless it's all automated it may still be a headache. Having to send out disbursements once a month is a lot less overhead.
In my business float is the big one - we pay our contractors at completion of work, which means if our clients pay us when they receive the goods, we’ve got to come up with the money to pay the workers before we’d gotten paid. This can get quite painful quickly, and meant in the early days we’d have to turn down large orders because we didn’t have enough float to pay the workers.
Automation makes the first one easier, but unless it's all automated it may still be a headache. Having to send out disbursements once a month is a lot less overhead.