These stats are from last season:
With Dembélé in the side Spurs won 51% of their games, compared to 44% without him. Without him, the loss rate was 44%, including both games against Saudi Sportswashing Machine, Southampton and West Ham. With him, Spurs lost just 2 games, a mere 7% of the time. Without Dembélé in the side, Spurs conceded 13 goals (1.44 per game) and scored 12 (1.33 per game). With him, 57 were scored (1.97 per game) and 22 conceded (0.76 per game).
You be the judge of whether we are better with or without.