Just because it's easier to make mistakes doesn't mean you can't properly debug your code. Writing good software in assembly language just takes longer. Also, the bug riddled thing makes it sound like you can't write good software in assembly language, which is obviously nonsense.
There is limit how large code base you can manage yourself. With assembly language you hit this limit sooner than with C language. And again in C language you probably hit this limit sooner than with C++. And so on. Very likely your project written in assembly language never grow to "full scale" as you get tired to maintain huge code base.
Asm makes it easier to make bugs because you must remember small details more. Which was not problem to me when I was writing in 68k asm but for example on Amiga you must remember to assign parameters to right registers. Using stack for temporary variables in asm is more difficult than in C. In asm you must count how many bytes you need from the stack and then calculate correct offset to access each variable in the stack. With good C compiler register usage is possibly more efficient because at least in theory it could compute optimal register usage in functions. In practise it isnt so, it seems.
But coding in 68k asm can be fun. I did that several years in the past.