Yes a difference but not that big, if you had one you would not need the other.
The 14mm is a better lens. Why fool around when you can simply step in most of the time?
I'm clearly not a fan of incremental measurbating.
I like 25mm as well but would always choose 21 on my way out the door.
If I showed an image taken with a 16mm and then stepped in (or cropped) with a 14mm it would be difficult to know which is which most of the time.
Objects close to the lens with either FL will be distorted.