Being able to find quality applications for my problems has been the biggest deterrent to me in participating, as a customer, in the Android market. I have not encountered any real problem in getting an application once I know it exists.
Whatever can make finding good solutions to my problems easy will become my first-class Android market. Right now I often find myself haranguing other people with Android phones or sifting through blog and forum posts in order to tease out what the quality applications are.
The sad part is I'd classify my mobile computer problems as really pretty simple compared to my lap/desk top problems. With my mobile (excluding communications) I'm almost always either trying to find/retrieve some specific fact(s) (how do I get from A to B, what is that star, is that a good price, what time was the meeting, show and tell with pictures, play music) or record some fact(s) (photos, voice, opinion on wine, exercise results).
This is a great feature. It's an example of a small, easy-to-implement change that makes their website just work better. I really like when things like this get done.
This is infinitely easier to support than building rubygems. Fortunately, the ecosystem that has been built around Rubygems.org is a far better solution than what we provided.
The difference is that they were actually building the rubygems for people. Here, you upload the already-built .apk, and the QR just makes it a little easier to have your phone download the .apk and install it.
It's my impression that the feature was dropped b/c it didn't solve the underlying problem with gem versioning/distribution.
Github got behind gemcutter early and urged everyone to make the switch. In the rare case when you want to install a gem version of an obscure fork, you can just install it as a submodule instead.
The inability to distinguish at a glance FOSS apps from closed apps has been one of the odd little components of the Android ecosystem for me.