I am very happy with my Cornercard with 1.5% cashback. During the summer and in special campaigns, they doubled the cashback to 3%. The yearly fee of the card is easily covered by the cashback, and insurance, concierge and lounge access etc. is included

https://www.cornercard.ch/

About the offer above, I don't think it is worth it really, for the cashback. As someone mentioned, most of the cashback is from the American Express card which is difficult to use. Try the calculator, with a monthly spending of 1000 Fr on the Visa card, you only get 24 Fr back at the end of the year.