I think that it would be much better for Sevilla to go down to the Europa League rather than continuing in the Champions League. Because clearly they can be more successful there. Sevilla have already started poorly to the season. On paper they got a lucky draw in the Champions League. But considering their effort these days I don't expect them to do better than Arsenal and PSV both. They can just make sure to get as many point as possible from Lens to consolidate the 3rd position.
When they go to the tournament in which they are called "the king" they can be much more successful.
That makes sense but sevilla can still at least earn some additional prize to help its club financially. Sevilla needs to get additional income for its club caused by the club has been suffering the horrible situation with its financial.
It's not necessary for the club to win UCL or reach final but it will be really helping the club so much. In fact, sevilla will get more money when it will go to the at least last 16 of UCL.
Goingback to the europa league will be only making sevilla to lose a good source of income. The club can use it as a motivation to do its comeback again. Although the probability of Sevilla succeeding is currently slim, their placement in a less challenging group still leaves room for possibility.
The poor performance shall not become an excuse for sevilla in competing with another club like arsenal or union berlin. I hope that sevilla will be able to be qualified for the last 16. It will be really helpful for the club to get additional fund.
The price play in UCL compared in europa league is far different.