What issues has she had? I sync between mobile - macbook -pc desktop every day and rarely have any issues, and all of them have been salvageable. This is over maybe 5-6 years of usage at this point.
It's a lot of cognitive overhead to remember not to touch Anki on any other devices unless you've synced and closed it out on the most recently used one.
Since she has a ton of cards, syncing takes a while. And occasionally it just throws a random error.
Moreover, there's a sense of fear every time she uses Anki that she will hit the wrong button and lose her expected state.
I haven't had any issues after remembering to do that, but I only really use text-heavy decks and not ones with lots of media.
Only a couple times over my entire usage have I actually had to do a full resync, and it's pretty painless. I just reupload to ankiweb, or download from it, and it's done. This is usually because I've caused some incompatibility via add-ons, or anki versions. But it's always been easy to fix.
>what other apps do you do that for?
I'm not sure what other apps I've used nearly as much as anki. Probably just firefox/chrome and emacs. I've had issues with losing tabs in browsers far more often than losing info with anki. And losing data by not saving in an editor is pretty easily done as well. I'm actually surprised at how well anki will handle changes from multiple sources. Unless you modify the same card on different devices, it pretty much always seems to work as expected.