@joelcrump Adding to other points made, a smartphone also means another device to have to remember and use, keep charged, etc. Accessibility on Android and iOS still has a ton of issues, and these are often at their worst during set up - OP hasn't mentioned these, but they're worth considering in a healthcare context.

If it's over an app as well, you can't just buy the cheapest Android phone, because odds are that won't have the power or the right version to run it (as I learned the hard way once). So that means extra cost in having to buy a sufficiently new model to run that app.

And given how many apps are just a wrapper for a Web page, there is almost no absolute reason for requiring an Android or iOS device specifically - people have mentioned Linux phones and devices too. And hell, Windows exists too. All of these can access a Web page just fine.

Plus, OP was initially told the app was optional.