There are actually many commonly used routes in Europe where this feature could be useful, e.g. the fastest route from Vienna, Austria to Bratislava, Slovakia includes exactly 2 km of Slovak motorway requiring a € 15 vignette just to drive on it once (and which are easily avoided using a 5-minute detour). Setting "avoid toll roads" altogether is way too drastic (the detour still includes a long section of Austrian motorway requiring a different vignette that is quite worth it even for a single journey).
Thomas Maes
There are actually many commonly used routes in Europe where this feature could be useful, e.g. the fastest route from Vienna, Austria to Bratislava, Slovakia includes exactly 2 km of Slovak motorway requiring a € 15 vignette just to drive on it once (and which are easily avoided using a 5-minute detour). Setting "avoid toll roads" altogether is way too drastic (the detour still includes a long section of Austrian motorway requiring a different vignette that is quite worth it even for a single journey).