It is possible that the recent trend led the bookmakers to give these odds to those teams. Chelsea has been doing much better in the last of couple of games. I still think they have a small edge in this game, but maybe not as much. However, betting on Betis Sevilla to win in regular time is quite risky. Yes the odds are worth it for some gamblers probably, but if I had to choose a winner in this game, I would go with Chelsea. Although I don't like the odds for them either as I think a draw after 90 minutes is very possible.
It won't be another boring finals without much actions. I will want the game to end as a full-time draw with Chelsea finally winning after extra time or during penalty shootout between these sides. With Nicholas Jackson back in the line up, I'm sure they'll be having that edge. They played brilliantly to contain Nottingham Forest and if they can do same against Betis, they're sure of lifting that trophy. They shouldn't underestimate Betis, they have an experienced manager who understands Premier League clubs like Chelsea quite well during European nights.