I don't think events impact performance too much compared to scripting. There are just certain things that are easier via script e.g making a battle system that has tons of different variables. Events that use pictures can also be greatly improved by either removing the need for 100 pictures for a health bar (one for each percentage) or by allowing them to be manipulated (rotated, resized, etc.) In your case, it would be the same either way unless you wanted to apply it to npcs aswell.