Why build your SC to the CubeSat standard?
Rapid development cycle – not “career satellites”
Large, open community
Reasonable chance of success (see track record)
Low per-mission costs (though high per-kg costs)
LEO orbits for now, GTO etc. later w/rad-hard.
LEO orbits are a relatively benign environment, therefore COTS components are OK
Now accepted as secondary payload
Current trends in technology (low-power, miniaturization, large feature set) are ideal fit to small spacecraft
No experience required!