Normally, when you ask a question you can begin typing a tag, and you will receive autocomplete suggestions based on existing tags. For example, the tag question-quality:
The system does not only give you suggestions based on primary tags, it also gives you suggestions based on tag synonyms. For example, bad-questions is a synonym of the above tag:
However, on the mobile app (iOS V. 126.96.36.199), tag synonyms do not exist:
So if someone is trying to ask a question using the app, they will be unable to find the question-quality tag via the synonym. They also will be unable to manually use the bad-questions tag, because apparently you also can't create a tag using the app:
As you can see, if no existing tag comes up, there is no option to add it.
There is already a largely ignored feature-request asking for the ability to create tags via the app.
But why are there no tag synonyms in the app? Is this a bug that can be fixed (with the obvious caveat that the app is not currently being worked on), or is this status-bydesign?