I use Safari for everything, and have never had problems with it – the number of times I’ve had to fall back to Chrome over the years is minuscule, and half the time it turns out the site is just broken, period. Obviously I don’t move in the same online circles as your wife so I probably don’t have the same online haunts that she does, but “it’s not a real browser” is nonsense. It’s a perfectly capable browser that performs better than both Chrome and Firefox in my experience.
My only real beef with it right now is that Apple is rapidly deprecating the HTML/CSS/JS-based extension platform and pushing devs to use a new app-based extension platform. I can understand why from a security standpoint – app-based extensions have way less insight into what a user is doing than the old platform, which is in line with Apple’s stated goal of protecting user privacy – but the new platform is still severely lacking in features compared to the existing one, and the barrier to entry into that market is way higher. So while it’s great that my ad blocker can’t spy on my activity in exchange for blocking ads because Safari just loads a pre-compiled list of blocking rules from the app’s extension, it also sucks that at the moment, it’s impossible to build something like Quickscript, Stylish, or AnyList’s recipe importer with app extensions, and there would be little motivation to try because now you have to build a whole app shell to stuff them into.