Because Lidl is lowering prices on 120 products for 25%
And don't forget, there's also Lidl Plus loyalty app.
And there are some days if you buy for 30 euros you get 5 euro discount
So Lidl just makes customers like it more and more.
Watch this video if you don't really understand what are we talking about.
So here you can see there is a poster on the Lidl building which says Lidl lowers prices of 25% on more than 120 products (It's in Greek)
The same thing says the leaflet and the Lidl Plus Loyalty program.