Agreed, but touchscreens and SD or USB means connectors, which are often a significant part of BOM cost and take up space. If you can do it all from the one-chip/module you have in there it's a big benefit when it comes to making something small and cheap.
Like I said, I've been fortunate to have alternate provisioning means.
I think the audio trick is a pretty elegant hack. Device agnostic and doesn't need a lot of handholding. But it also has an impact on the BOM. You need to add that Cortex M3 + microphone to sniff it out. Otherwise the whole thing could have been run off one chip like the ESP or GainSpan GS2100.
Doing the access point-to-client switcharoo is a good one too but needs a bit more instruction on the customer side, plus a way to whack the device back into setup mode when you need it.
