A braggart might construct a humble persona, but would a true braggart maintain such a persona for long? If they could, is there really any basis for calling them a braggart in the first place?
Being a braggart seems fundamentally incompatible with "not bragging", for years on end, about your greatest accomplishment (and barring the possibility that SN is somebody very famous, say, Putin, it is almost certain that bitcoin is the most famous thing that SN has done). Not in a "Scottish, but doesn't wear a kilt" way, but in a "Scottish, but does not live and was not born in Scotland" kind of way.
Being a braggart seems fundamentally incompatible with "not bragging", for years on end, about your greatest accomplishment (and barring the possibility that SN is somebody very famous, say, Putin, it is almost certain that bitcoin is the most famous thing that SN has done). Not in a "Scottish, but doesn't wear a kilt" way, but in a "Scottish, but does not live and was not born in Scotland" kind of way.