I discovered this by myself - I mean, the search button is right there! I must have been in the middle of a trip & searched for something, which pops up an "Add Stop" button. I think it's pretty discoverable.
I'm glad you discovered this, but let's look at a strawman grandma: "the search bar is where you type where you want to go, therefore if I search, it will turn off my current navigation / reroute my destination to whatever I am searching for".
The above is not a foregone conclusion, but it was how I thought until I read your and parent's postings about it, and I'm a techie. For every 1 techie that doesn't know about a feature, there are 1,000 users (or something like that).
I would posit that the discover-ability difficulties are present whether someone is in a TUI or a GUI.
I'm specifically referring to the Google Maps mobile app - it doesn't have a search bar, but has buttons that come and go depending on your current context. If a button is visible in your context, you can bet it works in that context. As an example, the layer, compass and search buttons are present when you're not navigating, but once you start, the layer and compass buttons are replaced by the audio chatiness button. The search button is still present, and the implication is that its usable in my current context: that's great discoverability in my book.
The above is not a foregone conclusion, but it was how I thought until I read your and parent's postings about it, and I'm a techie. For every 1 techie that doesn't know about a feature, there are 1,000 users (or something like that).
I would posit that the discover-ability difficulties are present whether someone is in a TUI or a GUI.