Every good and solid piece of advice you will get about making wordpress themes or frameworks will likely come with a suggestion to make it "child theme ready".
This is because many developers understand the massive inherent value in customizing a theme/base using a child theme, and they will want it.
The primary reason IMHO is that it makes future updates a lot easier as the changes you make are in a way "layered" on top of the base without changing the base.
You certainly don't have to. But if you don't, you will no doubt have people bugging you about it and suggesting it anyway. Not only that, but it will probably benefit you in the long run as it does make things more structured. In particular if you are leaning towards a framework.
Developing a theme so it is child theme ready does not add a lot more work or complexity, its just there are certain conversions you should follow. Most of which you should anyway when building wp themes.