Nope, it's not fine. It is a potential or actual problem. It certainly can cause a no-start condition if the corrosion residue present is heavy enough, and in your case it is so heavy that it looks like it definitely IS causing a problem! It doesn't take much to cause a no-start condition. But this is easy to fix.
Buy a battery terminal cleaner brush (they are very inexpensive). Do disconnect both leads from the terminals and clean both the battery posts and the cable ends. All are made of lead. The brush has two ends, one to clean inside of the cable terminals and the other to clean the posts. Remove all the powdery stuff that flakes off as it is highly corrosive. If necessary, clean up with a wet cloth with baking soda to neutralize acidic residue.
This should be done on a regular basis if you car is more than a few years old, and long before it looks like your photo does.
"An ounce of prevention is worth a pound of cure."