I have to agree with this, I really think that we do mods for a bit of attention or for people to possibly use our mods.
Not everybody have beta testers because not everybody has people interested enough in their work to test it or yeah, they are not experienced enough to know how to get them in a proper way, I am one of the later. I had people who wanted to beta test my mod, yet, none of them came to give back feedback. If I would have know better, maybe I would have find better people to test my mods.
And yeah, once you release it, it seems that people will come and report bugs so it can be a nice way to test your mod for the smaller bugs. I always put beta or demo somewhere in my mod description, and I will say it more than once, they are pretty much always in a working state too. People who release a beta with nothing in it though? That's another thing...