Depends mate, if your looking to restore it because you like the car and dont plan on selling it soon after, then yeah its worth doing. But if you want to make a profit out of the exersize then i dont think its the project for you!
remember, any car can be restored, depends on how far your skills go. You might want to consider re-shelling it? You can pick up a 3-door mk3 escort cheap enough and simply swap all the bits over.
If it was mine, i'd go for it mate!

street