Obviously, data needs to be digitized at some point. In my experience, even though it's duplicate work, users would rather reenter the data when they get home, on a PC, with a keyboard and mouse. ODK does have some decent tools for that, but they're all based on a dead standard, XForms.
Two major perks to using the ODK type tools - many folk have smartphones with browsers on them, so running ODKCollect or especially Enketo is accessible, and the logged data gets pushed up to a server as soon as possible. The latter point was really useful for us - I spun up a quick app in Shiny (https://www.shinyapps.io/) which would give some plots based on the data collected so-far, and after the first day or two the survey administrators found a hiccup in how one of the enumerators was answering a question (they were incorrectly tagging the locations they were visiting, which would have caused havoc to relabel later!) I think that sold a lot of us on the value of these tools.
Totally agree about XForms. Shame it's not more widely used. I did get a lot of mileage out of using XLSForm (http://xlsform.org/) to write the survey first though.
If you have an idea on how we could make this foundational tech more visible to other devs, shoot me an message!
On the other hand, bring-you-own-device is a risky business move anyway because App Store rejection is a very real concern. It was a problem more than once for that project.