Design and coding are different because they serve different purposes:
Design = planning (how it looks, feels, and works)
Coding = building (writing code to make it work)
Design answers “what and why”
Coding answers “how”
Design is harder cause it deals with a lotta aspects of what your target users need and prefer.
Design is simply about deciding how to build the application, what colors to use... it's basically your development plan.
Coding is simply, typing the code.