I have been using the discovery tool with great success for a long time.
I think it has been one of the best tools the Spotify team brought to the service, because it managed to very frequently suggest music that was similar to my tastes
For reasons that I do not understand, today my "discover" tab has been literally "spammed" by what is "trending" near me, or what is "popular" in my area, or what is "popular" right now in Spotify.
Suddenly 99 out of 100 suggestions are completely irrelevant to what I have in all my playlists - so the discover tab is completely destroyed.
I think that this is actually a bug - discover/suggestions should be affected by your listening habits, and not by where you live.