The main reason people think Sevilla is a strong team is they just see the results they get and they don't pay attention to the situation of the games they have,
People think that if how many trophies being collected by the team will always represent how strong that team is. I do know if sometime this can't be used as a benchmark but im thinking about this is still making sense to call the team was strong.
That proves how consistent the club in winning the competition, right? The fact that if sevilla is strong enough right now consider it has beaten so many candidates from another club.
I would not be surprised to see some people counted how many UEL trophies have been colected by sevilla as a thing that was also affecting the performance from the club.
You are right, having trophies on a particular league doesn't guarantee you the winner of the ongoing league when you are not in a strong form. Juve is in a strong form than Sevilla and I don't think that Sevilla will be able to win Juve and qualify to the finals. Sevilla won Girona last weekend is not enough for we to use this victory to give them accolade that they will win Juve. Football is full of surprises and we should expect the unexpected.