I can't vouch for the potential for larger erections as the information presented was found during a quick Google search, and I have been circumcised. It could be that a number of people simply believe this without scientific evidence. However, I have checked my penis very thoroughly for many many years and can't definitely say with 100% accuracy that it does not produce smegma. Depending on the quality of circumcision, I imagine that some penises may produce a small amount of smegma. You should check your penis and we can compare notes.
It doesn't make sense that an uncircumcised male doesn't produce any, since I believe smegma is made up of dead skin cells and natural body oils, which become trapped under the foreskin of an intact male. Since the penis is covered in skin, and since there is no question that skin cells die and undergo exfoliation, my best guess is that there simply isn't anywhere for the smegma to collect in a circumcised man.
You don't really need a penis to figure that out.
Relax... I'll need some information first. Just the basic facts - can you show me where it hurts?