I love how in the manga both Jotaro and Star Platinum are smiling/smirking more in general and that kind of gives Jotaro's character a feel of cockiness and a little bit of arrogance which I like for the character development, it makes his seem a bit more human because he is mostly poker faced, mainly in the anime, not showing much emotion. And for Star Platinum smirking is better. I always found it a little bothering that Star Platinum was so emotionless because he was one of the few stands that has quite a human like face, so smirking does suit him more, also because he is quite powerful and violent, described by Jotaro to be wilder than him so I imagine him putting on a more cheeky expression like in the manga
But being poker faced is a part that makes Jotaro so badass so it's still good