Being a strong swimmer isn't much help against overconfidence or panic.

Learning how to be careful is really important, and weaker swimmers are often more cautious.

The other big problem is that you might be safe but someone less skilled copies you. I was being very careful in knee high shallows near a well sign-posted rip in South America, and some teens got in and got taken out by it. Fortunately they made it back (nobody near could have helped them).

Or even in the USA: "TikTok discovered scenic Eagle Falls; then 12 people drowned" https://news.ycombinator.com/item?id=44446535

I've definitely had some close calls from poor decisions in rivers and the sea (I can be reckless at times).

Yes, not panicking is a distinct skill from being capable and needs to be practiced explicitly. But the latter does tend to make the former easier.