There's one advantage of foo.bar calling a function, it works well with referential transparency. Whether it's a property/value or function, only the result matters. I can't say it's a big difference though, I've only been mildly annoyed by having to change all call-sites when changing between them. Other languages allow code bodies for getters/setters (foo.bar = ...) so it still hides the call. For a C-style syntax language having the () seems less surprising.
When it comes to correctness, only the result matters, sure. But not so for performance and code understandability. Obscuring points of arbitrary code execution is awful.
The getter/setter pattern is also bad, but a little less so since it's exceedingly rare any real code will get executed there.
