There's 2 very different kind of placeables:

1. Static
2. Non-Static

While it is a simple “checkbox” in the placeable properties, it changes a lot of things.

• They can be targeted by players
• They can be animated / have visual effects
• They can be moved
• They are only seen by players when their character gets in a perception range of the placeable
• Since that are loaded by players dynamically, many non-static placeable can make walking around an area laggy for players. Areas shouln't have more than 100-200 non-static placeables.

• They are loaded by players when loading the area
• They can't be targetted, be animated or have visual effects, moving them wont by perceived by players until they re-enter the area
• They don't really impact players performance so you can add almost as many as you want to your areas (but ideally less than 1k)