On the app, the only way you can filter by your favorite tags is by using the unanswered (my tags) filter. However, this brings up very old questions (dating from more than a year, which have less value because noone is actively waiting for an answer one year later). It would be better to see the latest questions, like what you can see on the site when selecting a tag.
When I'm on the app, I usually want to do one of the following
- Check my feed, to look at hot questions, responses, comments in answers I have posted
- Look for new questions I could answer
For the point 2., it's very important to me to be able to find questions I could possibly answer. These questions are the questions tagged with my favorites tag, and it seems natural to me that the newest question should appear first, as questions asked more than a week ago are not very likely to find an answer and the OP has probably no more interest in that question.