The flag OSM geocoder is Nominatim. It turns out it won't work if you provide only part of street name (if OSM contains full street name) or when you provide full name (if OSM contains only part of the name) [1]. So in my opinion searching for addresses is not reliable.

That's one thing, another is that addresses are quite often duplicated. There's no automatic check for that and such duplicates exist for years.

[1] - https://help.openstreetmap.org/questions/45825/how-can-i-geo...