only the low impedence/low ESR caps are needed in the output section. Regular caps are fine on the line section. 

Low ESR caps wernt used from the factory only if they wernt available, or they wanted to produce them cheaper. But using regular caps do shorten their life, as they heat up more from the ripple current induced from high speed switching. 

However, you can get cheap 85c caps and still be low ESR, or low enough to where the power supply currents wont affect it. But generally as a rule of thumb, the ESR has to be low..