An average mark is just that. An average. But companies don't need people that are good in everything. They need people that are good in their thing.
If for example, you are looking to work in Wolfsburg, Stuttgart or Hildesheim, a great master thesis about automotive/embedded computing is worth more than any average mark.
If you are looking to work for a financial instituition, your grades in BWL/VWL might be looked at more closely, while if your worked for Greenpeace they might look favorably at the fact that you arrived by bike or public transport.
There's two sorts of employers that actually look at average grades: The big ones like Microsoft and Google, just because they can. They can filter for grades first and still have enough applicants to hand pick those they want. And then there's the buerocratic ones like unions, public offices, academia and the like. They filter, because they don't know better. They aren't looking for the best for the job, they are surprised someone will actually work for that little money.
So normally it comes down to the following order:
- work experience
- any other experience of the kind the company is looking for (master thesis, optional courses, marks in those courses they are interested in )
- personal charisma
- average marks
Obviously, this is a slightly weighted scale. If your average is 1.0, I don't need to look at your BWL marks explicitly, if your average mark says "failed", I'll probably not invite you.
Find your thing and look for the company that is looking for it and you won't have problems with average marks. That doesn't mean that there isn't someone out there who's even better than you at your thing, but for every job he gets, there is one less competitor for the next job offer.