A pellet grill is a convection oven that burns wood. The controller is the part you are really buying — it decides how tightly the cooker holds a set temperature and how it behaves when the weather turns.
What a pellet grill is good at, and what it is not
Unattended long cooks at a stable temperature are where these cookers earn their price. Searing is where most of them struggle: the fire pot is small and the airflow is designed for smoke, not for the radiant heat a steak wants. Treat a sear attachment as a separate purchase decision rather than a bonus feature.