To me, casting is about the rod and the line. The reel plays a smaller role in casting.
If you want to improve your casting such as accuracy and distance, rod and line are your major players.
Reel is there to hold the line, drag to fight the fish, and yes can determine how smooth the line comes out.
Your casting is probably still terrible using a Stella reel if you're casting with a $5 cheap wrinkly mono with $20 kmart rod.
On the other hand, you will get much better casting (accurate and good chance of better distance) using a good graphite rod and a good braid line though with a $50 Sienna.