Python is a good language for writing glue code. Django abstracts a lot away with its ORM. If you stick to just providing an API, you'll still get some help from it.
Now is it better than assembling a little stack yourself with an ORM + a micro web framework? Well, perhaps not - though you still got the admin which can be handy. But next time you're going to need do to a project that won't benefit at all from being a SPA, Django will be helpful.
You can turn the question on its head - if you're just providing a relatively thin API, whatever you choose probably won't be terribly important as long as it is not something fragile that will be gone in 2 years. So don't invest too much thought into it.
