To over simplify - ignoring alloy materials that increase toughness - harder steel means more brittle.
Japanese knives are harder - about 60-67 HRC.
European knives are traditionally 55 HRC or less. Recently that has changed as Japanese knives gain more popularity.
Given the same alloy, Japanese knife makers will harden their blades more. Japanese blades are also thinner. In the hands of somebody who doesn't properly use their knives, this leads to chipping. At one internet vendor's website, they have a lengthy explaination for the Moritaka gyuto, also saying your misuse is not their problem.
It isn't a professional/home cook issue. Wustof's and Sabatiers are soft. This can be traced back to Bronze Age China - they simply chose to make harder blade and it stuck.
If you know what you are doing, it isn't an issue. If you choose the right tool for you, it isn't an issue. When in doubt, choose the tougher blade.
Notice EDC knives are softer, <60 HRC typically. There are a few exceptions. Meat cleavers, European swords, and such are normally <50 HRC, usually 44-45 HRC. Machetes usually have lower carbon content and aren't as hard. Hardness is sacrificed for toughness.
A European Chef's knife and Japanese Gyutos aren't exactly direct replacements.
A European chef's knife is meant to be able to do light butchery. The heel is much thicker and the bolster can be used to break chicken bones. The tip is thin and can be used for detail work. So it handles meat as well as vegetables, but has the unfortunate tendency to crack crisper, taller foods like melons or large carrots. Within European cuisine, it is very versatile and handles everything.
The Japanese have a specialty knife for everything. Meat, besides fish, is not a traditional part of the diet. A deba is used to break down fish. A gyuto is lighter and thinner, a precision instrument. You'll note Japanese cuisine also has far more thin slices. The gyuto handles a narrower range of tasks, but does them very well.