Most of the people pick origin, because it gives more "features", than making your own "main" character.
has larian posted somewhere that most ppl pick origin characters? bc my read on the forums is that most ppl will play origin characters 'if theyre there' but would prefer playing and making their own 'main' characters, particularly if the 'main' charactacter got some of the 'features' that seem to be limited only to origin characters, which i think is the core issue of the origin characters v custom pc in that the custom character doesnt have access to the same gameplay mechanics or have their own personal/unique plot hooks/storyline when compared to the origin characters.
admittedly im biased here bc i dont think its a good game design for a franchise (BG/dnd) that espouses unique/'create your own' character creation where you play your own story/adventure - why would i want to play as a dev written dmpc? if the origin characters were just fleshed out npcs i wouldnt have that much an issue, but i dont understand the insistence and writers/resources being allocated by larian for upwards of 8 origin characters and it just seems like a larian hold-over from dos1/2 (as is evident in other gameplay mechanics). frankly, the more time spent on origin character integration by larian makes me think its less likely that we will see 6 party slots or a large variety of 'fleshed out' non tadpole npc companions, but hope to be proved wrong