The ECML does run alongside the coast for a while near Berwick, the WCML I think was probably named because as such because it goes up the West side of the country.
One advantage the WCML does have is that it enables me to go to the Lake District for a day from home if I want. I can drive it, but I would be too tired to do anything once I got there and would dread the drive home, but I can be there in a couple of hours from Wolverhampton to Oxenholme Lake District without having to change trains.