You could say that if an invention is any good it speaks for itself, in which case you've saved yourself the effort of bragging and people still get to know about it
Good inventions usually look bad from outset. Otherwise someone else would have come up with them much earlier. So, you still need to sell your inventions and get people to see the potential.
A good invention might speak for itself if you give it 20 years and wait. But you can't run a business if your marketing strategy involves "wait 20 years".
