It was the cinematic equivalent of a theme park ride, which is what a lot of people went to the theatre to experience. Althiough it was a poorly written and extremely corny romantic drama, there's a huge audience for that too, if Sandra Bullock's bank account is any yardstick. And it was handsomely produced at the pinacle of film making craft for its day. So the box office receipts shouldn't come as a surprise.
The acting was easy to understand, the leads are capable of much better, but I'm guessing were instructed to play it broadly so that they stood out against the lavish backdrop of the production. The rest of the cast played their parts at the level of a local opera company.
A film goer who found My Dinner with Andre compelling viewing would be overwhelmed. A person who thinks that doing DisneyWorld and Epcott Centre in the same day is a relaxing day of vacation would have found this fine entertainment.