In my opinion, it's not "pythonic" to use DBMS, just because it written in python.
So the "selling point" is flawed.
Disclosure: I'm using python since 2006. I've made a lot of evangelizing it. It is my weapon of choice for many tasks. And I will never use python for many other tasks. (Don't tell me about PyPy or Stackless)
I get your point and I'm all in for being language-agnostic when it comes to the tools I have to use, but that doesn't change the fact that convenience plays a role when you are in a point where you can't affort a long-term decision process. the best technology to quickly launch something is most often simply the one you know.
[1] Python works well with other languages of course, and is often used as a "glue" between other components.
[2] This assumes that you know Python better than whatever language it was made in, but for many cases that will be true.
[3] I often like to look at libraries just to understand how they work, but that is different. There are often cases, especially where the tool uses some abstraction that can leak, where you need to look under the hood just to get things working.
(We have 45% of .NET-ters, 35% of javers, 20% : devDBAs, Js-ers, others)
My propaganda is always: "Be programmers, mazafakerz!" And python is excellent tool for explaining ideas between this groups. Javer will not be offended if I show him .NET-code and otherwise.
For them python is "executable pseudo-code".
It will be sad for me if pythonistas became a caste like .NET, Java ... and Haskel (they are not a caste but have all possibilities to became one)