Yes, it'd be great if the audio recording function worked within the Moodle app. In my context, second & foreign language learning & teaching, audio submissions are an important part of mobile LX design. I was chatting with a guy yesterday who was considering which platform to use for mobile-focused learning & on of his main criteria was a seamless record & submit process with as few stages as possible, pretty much the way that Moodle now does it in the web browser. He was more drawn to Wordpress with LMS plugins & developing mobile app wrappers rather than what should be the better, simpler, more stable route of Moodle & app.
At the moment, learners have to switch from the app to a web browser on their phones in order to submit. Additionally, they can't record offline, which is also a popular request I've heard. Explaining that they can use their phone's software to record & save audio isn't really a feasible option as this would increase the demand learner training & support substantially.
Recording & submitting audio within the app as simply & smoothly as possible would be fantastic if you can get it to work!
Just my $0.02!