I can share an anecdote from the reverse perspective. When traveling in Morocco, I didn't speak any local languages (eg, French or Arabic). I also was entirely unfamiliar with the city, the distances between points, or even how much something should cost. If there was a Yandex app, I wouldn't have known about it (... although the last time I was in Morocco predated smart phones by about 10 years).

This meant that negotiating a price was pretty much out -- I paid what they asked, and had no real way to gauge whether that was reasonable other than asking a local. I also had no recourse if they overcharged -- what was I going to do?

Information asymmetry is a potent weapon for taking advantage of people, whether it involves taxi rates, or just how clean the restaurant's kitchen is, or how fresh the ingredients are. This is why we have regulations that attempt to provide some of the symmetry required for fair exchange.