What is it with physicists and programming? I know at least 3 people who started having physics degrees, but left it completely for programming. Mind you they are all excellent coders and sharps as hell... but this is not an uncommon profile it seems.
1. A non-negligible amount of physics research involves programming. Analyzing large amounts of data in ways that (hopefully) no one has ever considered before is not something you can easily do by hand anymore.
2. Physicists are taught to see the world as reductionists: complex systems are broken down into smaller, more understandable parts. Hell, most of physics is reducing things to take advantage of symmetries, or approximate interactions as harmonic oscillators (springs), or a small number of other very well understood/studied phenomena. The hard part is making sure your reductionist assumptions and approximations are correct.
3. High-end physics research positions at universities are very few and far between (and are very much a boys club of nepotism with regards to hiring), and even those don't offer the kind of compensation that you see for mid-level software developers in tech companies.
4. After you've learned how to read & interpret publications in physics research, most computer science papers seem tame in comparison.
Incidentally, the reasons I described above are also why many physicists end up being hired by investment banks or hedge funds. Out of all the people from university I still keep in touch with, I think only one of them is doing actual research in physics. The rest are working in tech or at a bank/fund.
Now fast-forward to today, when 8-bit controllers are pretty much a thing of the past and ARM Cortex-Mx processors are the way to go. Setting up C/C++ cross-development is a bit more challenging. Writing enough code to get out of reset, get your I/O mux'es set, and actually wiggle an output pin is a lot of work. What Micropython does is turn a USB cable into a development environment that allows you to try things on an ARM a few minutes after your PyBoard arrives in the mail. It also provides a BSD-licensed base of code that works with a well-defined and easy to install build chain so that you can reflash the part with a custom build of your liking. So for the performance-critical parts, you can write a C extension, if it comes to that. But a little bit of in-line assembly (which Micropython supports) might be all you need.
TL;DR: You can avoid a lot of time-consuming heavy lifting and focus your energy on the part that matters to you, accessible through a very powerful language.
I'm admittedly a Micropython partisan. But FWIW I have been doing embedded development off-and-on since the 6502 was the hot new chip (yes, gray beard and all) and to me Micropython is the most interesting development in embedded development since Arduino.
All that said: Is it really a viable way to ship a commercial product? I say yes: 1. The licensing is there. 2. You can easily write C extensions for the performance critical parts. 3. Python should give you time-to-market advantages over C-on-the-bare-metal.
Now that one can buy a 100+ MHz 32b CPU with 256KB RAM and 1MB of FLASH for $5 (and dropping), using assembly or C to make it fit into an 8b PIC with 2KB of RAM to save $3 isn't a worthwhile trade off for many applications.
So that would seem to make actual Python a better candidate for Android porting. I found http://qpython.com/ which seems interesting, but the site didn't look finished.
With ESP8266 port kickstarter, Android port is put on hold.
One option for interacting with java from python is to use tools like pyjnius (http://pyjnius.readthedocs.org/en/latest/) - this is what e.g. Kivy does to get system information like screen metrics.