What you hope is that the gains in revenue outweigh the gains in costs, to support purchasing a commercial property over a residential one.
Bigger initial investment. Acquiring a commercial property typically requires more capital up front than acquiring a residential rental in the same area, so it's often more difficult to get your foot in the door. Once you've acquired a commercial property, you can expect some large capital expenditures to follow. Your property might be humming along for a few months and wham, here comes a $10,000 bill to address roofing repairs or a new furnace. With more customers there are more facilities to maintain and therefore more costs. What you hope is that the gains in revenue outweigh the gains in costs, to support purchasing a commercial property over a residential one.