1) CC is slow, at least in Switzerland. Like in Germany, efficiency is baked into the culture - people hate to wait on someone paying his chocolate bar with credit card. It's also not rare for people to show you that discontempt. This trains people into behaving.
2) Switzerland, as most of Germany, is a mostly urbanized place with good public transport and facilities close to where people live. Meaning, there's way less weekly mall-shopping going on than in less dense countries like the US or France. So, the average total price is lower since shopping trips are more frequent, often about every second or third day after work.
3) Security concerns. For a long time CC were as insecure as the US ones, with a simple swipe of the magnetic stripe being sufficient, and CC fraud was relatively frequent. So, many people have an instinct of only using CC when necessary, and if at all possible not in public places. Debit card on the other hand have always been relatively secure (6-digit pin code, 3 tries), so they are used more often, maybe more so than in the German example since Swiss banks have pushed them since around 20 years ago.