A 60w iron will break the pads much easier than a 15w. Generally removing SMD caps is easy with a 15w, but rather dangerous with a 60w one. At least if the tip is very big, as they often are on the big boys. Maybe it's just my 40w iron from the late 70s with a big tip that is too powerful... That's why I love my 15w
Regarding the ground plane, yes, that's where a higher-wattage solder iron is handy... But still, working with SMD components with a 60w iron is nonsense in my head.
EDIT:
666 posts!